<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2024 Workiva-->
<!--r:4356ab70-680d-417e-86dd-187943ef9624,g:30f3b3bc-9731-4522-9912-31a8c6bf4a47-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.westlake.com/role/ConsolidatedBalanceSheets" xlink:type="simple" xlink:href="wlkp-20240930.xsd#ConsolidatedBalanceSheets"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/ConsolidatedBalanceSheets" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_6f28cfbf-e666-42ca-b99a-7285dee1f7c6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_f637e273-48c5-4cd8-b42d-3809b20bab48" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_6f28cfbf-e666-42ca-b99a-7285dee1f7c6" xlink:to="loc_us-gaap_StatementTable_f637e273-48c5-4cd8-b42d-3809b20bab48" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_8e4acfe5-c7f0-4cbb-9209-07f66ed900f9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_f637e273-48c5-4cd8-b42d-3809b20bab48" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_8e4acfe5-c7f0-4cbb-9209-07f66ed900f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_8e4acfe5-c7f0-4cbb-9209-07f66ed900f9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_8e4acfe5-c7f0-4cbb-9209-07f66ed900f9" xlink:to="loc_us-gaap_RelatedPartyDomain_8e4acfe5-c7f0-4cbb-9209-07f66ed900f9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_54c0bab1-fcbe-4182-b287-1068c9c34fe3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_8e4acfe5-c7f0-4cbb-9209-07f66ed900f9" xlink:to="loc_us-gaap_RelatedPartyDomain_54c0bab1-fcbe-4182-b287-1068c9c34fe3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_29d96eca-a7de-4b33-99de-a69192aaa56a" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_54c0bab1-fcbe-4182-b287-1068c9c34fe3" xlink:to="loc_srt_AffiliatedEntityMember_29d96eca-a7de-4b33-99de-a69192aaa56a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonrelatedPartyMember_29704496-46ed-4278-8f1d-cffcc32736cb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NonrelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_54c0bab1-fcbe-4182-b287-1068c9c34fe3" xlink:to="loc_us-gaap_NonrelatedPartyMember_29704496-46ed-4278-8f1d-cffcc32736cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_481a7858-6b93-457a-bab7-c333640e99c8" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_f637e273-48c5-4cd8-b42d-3809b20bab48" xlink:to="loc_srt_CounterpartyNameAxis_481a7858-6b93-457a-bab7-c333640e99c8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_481a7858-6b93-457a-bab7-c333640e99c8_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_481a7858-6b93-457a-bab7-c333640e99c8" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_481a7858-6b93-457a-bab7-c333640e99c8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_587b2052-2121-4535-bac6-e9b0b477bca4" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_481a7858-6b93-457a-bab7-c333640e99c8" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_587b2052-2121-4535-bac6-e9b0b477bca4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_UnidentifiedThirdPartiesMember_f3cfc4ce-b14d-40d8-9041-fee87f925e91" xlink:href="wlkp-20240930.xsd#wlkp_UnidentifiedThirdPartiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_587b2052-2121-4535-bac6-e9b0b477bca4" xlink:to="loc_wlkp_UnidentifiedThirdPartiesMember_f3cfc4ce-b14d-40d8-9041-fee87f925e91" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_b8274fdb-3884-4c6e-a7bc-416a2119ef3d" xlink:href="wlkp-20240930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_587b2052-2121-4535-bac6-e9b0b477bca4" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_b8274fdb-3884-4c6e-a7bc-416a2119ef3d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_650a99a2-1afa-41e7-95e4-54f8aea7f1b1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_f637e273-48c5-4cd8-b42d-3809b20bab48" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_650a99a2-1afa-41e7-95e4-54f8aea7f1b1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_650a99a2-1afa-41e7-95e4-54f8aea7f1b1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_650a99a2-1afa-41e7-95e4-54f8aea7f1b1" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_650a99a2-1afa-41e7-95e4-54f8aea7f1b1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_570dc400-4b11-4df9-ac3c-254e6c17b5df" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_650a99a2-1afa-41e7-95e4-54f8aea7f1b1" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_570dc400-4b11-4df9-ac3c-254e6c17b5df" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CommonUnitsMember_3936c125-e069-4ab0-8a16-73019d0d6c3a" xlink:href="wlkp-20240930.xsd#wlkp_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_570dc400-4b11-4df9-ac3c-254e6c17b5df" xlink:to="loc_wlkp_CommonUnitsMember_3936c125-e069-4ab0-8a16-73019d0d6c3a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_66334b0f-dfbc-4c2c-8a61-3cca09540d4e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_6f28cfbf-e666-42ca-b99a-7285dee1f7c6" xlink:to="loc_us-gaap_AssetsAbstract_66334b0f-dfbc-4c2c-8a61-3cca09540d4e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrentAbstract_6bf4c981-02d7-4545-9aaa-cf1f86278dc7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AssetsCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_66334b0f-dfbc-4c2c-8a61-3cca09540d4e" xlink:to="loc_us-gaap_AssetsCurrentAbstract_6bf4c981-02d7-4545-9aaa-cf1f86278dc7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_4abfcd0f-6cd8-47fd-b80d-3ab7e379b80d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_6bf4c981-02d7-4545-9aaa-cf1f86278dc7" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_4abfcd0f-6cd8-47fd-b80d-3ab7e379b80d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ReceivablesunderInvestmentManagementAgreementswithRelatedPartiesCurrent_ae434db0-0590-42ea-9d40-edc61286a3ff" xlink:href="wlkp-20240930.xsd#wlkp_ReceivablesunderInvestmentManagementAgreementswithRelatedPartiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_6bf4c981-02d7-4545-9aaa-cf1f86278dc7" xlink:to="loc_wlkp_ReceivablesunderInvestmentManagementAgreementswithRelatedPartiesCurrent_ae434db0-0590-42ea-9d40-edc61286a3ff" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_7435ad44-0c05-4eee-ac86-bf0b9622f62a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_6bf4c981-02d7-4545-9aaa-cf1f86278dc7" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_7435ad44-0c05-4eee-ac86-bf0b9622f62a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivablesNetCurrent_67147791-e620-4df7-a1bc-55e301ac5ff2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ReceivablesNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_6bf4c981-02d7-4545-9aaa-cf1f86278dc7" xlink:to="loc_us-gaap_ReceivablesNetCurrent_67147791-e620-4df7-a1bc-55e301ac5ff2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNet_5067b952-dbfb-468c-88ce-a78226333b6b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InventoryNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_6bf4c981-02d7-4545-9aaa-cf1f86278dc7" xlink:to="loc_us-gaap_InventoryNet_5067b952-dbfb-468c-88ce-a78226333b6b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_b3996034-8c52-49b2-9961-3d1dd3c70a2c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_6bf4c981-02d7-4545-9aaa-cf1f86278dc7" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_b3996034-8c52-49b2-9961-3d1dd3c70a2c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_d380abd0-5898-45b0-9375-ed67bb4228ad" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_6bf4c981-02d7-4545-9aaa-cf1f86278dc7" xlink:to="loc_us-gaap_AssetsCurrent_d380abd0-5898-45b0-9375-ed67bb4228ad" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_c3ced781-14b1-48a6-a282-ce12f8c10207" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_66334b0f-dfbc-4c2c-8a61-3cca09540d4e" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_c3ced781-14b1-48a6-a282-ce12f8c10207" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_64a52d53-1425-46db-a718-e3c66b622bdb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_66334b0f-dfbc-4c2c-8a61-3cca09540d4e" xlink:to="loc_us-gaap_Goodwill_64a52d53-1425-46db-a718-e3c66b622bdb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCostsAndOtherAssets_cbcfa4ef-5987-4f24-9cf7-aa2b1ce23074" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DeferredCostsAndOtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_66334b0f-dfbc-4c2c-8a61-3cca09540d4e" xlink:to="loc_us-gaap_DeferredCostsAndOtherAssets_cbcfa4ef-5987-4f24-9cf7-aa2b1ce23074" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_f627e306-c294-43a5-a776-f0faf41dd429" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_66334b0f-dfbc-4c2c-8a61-3cca09540d4e" xlink:to="loc_us-gaap_Assets_f627e306-c294-43a5-a776-f0faf41dd429" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_a1df786f-f052-4738-bade-ce3125b1bd8a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_6f28cfbf-e666-42ca-b99a-7285dee1f7c6" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_a1df786f-f052-4738-bade-ce3125b1bd8a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_df489f6b-fc05-4db5-a168-093422e5d93d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_a1df786f-f052-4738-bade-ce3125b1bd8a" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_df489f6b-fc05-4db5-a168-093422e5d93d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_eec8800d-403d-4bd4-8a02-059529744572" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_df489f6b-fc05-4db5-a168-093422e5d93d" xlink:to="loc_us-gaap_AccountsPayableCurrent_eec8800d-403d-4bd4-8a02-059529744572" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_5631f342-f2bb-45ce-9dc9-ba95b07d7a85" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_df489f6b-fc05-4db5-a168-093422e5d93d" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_5631f342-f2bb-45ce-9dc9-ba95b07d7a85" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_12c28663-69d0-4578-b9fb-bb44191eca7f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_df489f6b-fc05-4db5-a168-093422e5d93d" xlink:to="loc_us-gaap_LiabilitiesCurrent_12c28663-69d0-4578-b9fb-bb44191eca7f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLongTermDebtNoncurrent_418d0638-14ae-4423-a419-688f8773285b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherLongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_a1df786f-f052-4738-bade-ce3125b1bd8a" xlink:to="loc_us-gaap_OtherLongTermDebtNoncurrent_418d0638-14ae-4423-a419-688f8773285b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_e39b8cef-b483-4eb9-b047-a2da71f9c1be" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_a1df786f-f052-4738-bade-ce3125b1bd8a" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_e39b8cef-b483-4eb9-b047-a2da71f9c1be" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_f002cc95-bbd0-4cb0-a1ed-1430e968e5e7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_a1df786f-f052-4738-bade-ce3125b1bd8a" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_f002cc95-bbd0-4cb0-a1ed-1430e968e5e7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_a1adb72c-aaa8-4ab9-87b0-5ed717fdda71" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_a1df786f-f052-4738-bade-ce3125b1bd8a" xlink:to="loc_us-gaap_Liabilities_a1adb72c-aaa8-4ab9-87b0-5ed717fdda71" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_51186514-fc49-402b-9a8b-6c659679129f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_a1df786f-f052-4738-bade-ce3125b1bd8a" xlink:to="loc_us-gaap_CommitmentsAndContingencies_51186514-fc49-402b-9a8b-6c659679129f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityAbstract_03003592-3cbc-4ad9-bba7-07e174fa61a5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_6f28cfbf-e666-42ca-b99a-7285dee1f7c6" xlink:to="loc_us-gaap_StockholdersEquityAbstract_03003592-3cbc-4ad9-bba7-07e174fa61a5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccount_c0d8e9ca-b1ce-4a0d-bbb9-e14d2f9e80fa" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_03003592-3cbc-4ad9-bba7-07e174fa61a5" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccount_c0d8e9ca-b1ce-4a0d-bbb9-e14d2f9e80fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralPartnersCapitalAccount_5bbe9acb-1f17-475b-9509-9f63c671b0c9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GeneralPartnersCapitalAccount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_03003592-3cbc-4ad9-bba7-07e174fa61a5" xlink:to="loc_us-gaap_GeneralPartnersCapitalAccount_5bbe9acb-1f17-475b-9509-9f63c671b0c9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapital_f038bfe4-ef40-4fe3-8c3f-faef135aee17" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnersCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_03003592-3cbc-4ad9-bba7-07e174fa61a5" xlink:to="loc_us-gaap_PartnersCapital_f038bfe4-ef40-4fe3-8c3f-faef135aee17" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestInLimitedPartnerships_ae5a7a79-4aa6-4abd-964d-541d3a0087be" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_MinorityInterestInLimitedPartnerships"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_03003592-3cbc-4ad9-bba7-07e174fa61a5" xlink:to="loc_us-gaap_MinorityInterestInLimitedPartnerships_ae5a7a79-4aa6-4abd-964d-541d3a0087be" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_e3939839-95d7-4af9-b83a-3ea16783be50" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_03003592-3cbc-4ad9-bba7-07e174fa61a5" xlink:to="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_e3939839-95d7-4af9-b83a-3ea16783be50" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_9fb29719-e0df-40ee-8bc3-ac802bd1b639" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_03003592-3cbc-4ad9-bba7-07e174fa61a5" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_9fb29719-e0df-40ee-8bc3-ac802bd1b639" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" xlink:href="wlkp-20240930.xsd#ConsolidatedBalanceSheetsParenthetical"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_99b14fab-22b2-41fe-8a85-c5fe48e27885" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_da18b4e0-cd10-4ae8-b283-39544c65bc0e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_99b14fab-22b2-41fe-8a85-c5fe48e27885" xlink:to="loc_us-gaap_StatementTable_da18b4e0-cd10-4ae8-b283-39544c65bc0e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_230185c4-28be-4a24-8613-354668bf23a9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_da18b4e0-cd10-4ae8-b283-39544c65bc0e" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_230185c4-28be-4a24-8613-354668bf23a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_230185c4-28be-4a24-8613-354668bf23a9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_230185c4-28be-4a24-8613-354668bf23a9" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_230185c4-28be-4a24-8613-354668bf23a9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_8f02c546-bea1-4bb8-8b3d-b9f1e8e5dd15" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_230185c4-28be-4a24-8613-354668bf23a9" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_8f02c546-bea1-4bb8-8b3d-b9f1e8e5dd15" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CommonUnitsMember_214ec310-4e82-4116-8e9d-9e76f513d6ed" xlink:href="wlkp-20240930.xsd#wlkp_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_8f02c546-bea1-4bb8-8b3d-b9f1e8e5dd15" xlink:to="loc_wlkp_CommonUnitsMember_214ec310-4e82-4116-8e9d-9e76f513d6ed" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_54d75e15-17e4-45b7-bc6d-38e143a44837" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_da18b4e0-cd10-4ae8-b283-39544c65bc0e" xlink:to="loc_srt_CounterpartyNameAxis_54d75e15-17e4-45b7-bc6d-38e143a44837" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_54d75e15-17e4-45b7-bc6d-38e143a44837_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_54d75e15-17e4-45b7-bc6d-38e143a44837" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_54d75e15-17e4-45b7-bc6d-38e143a44837_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_ac1021c0-6ebb-4689-a58e-15485da186f7" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_54d75e15-17e4-45b7-bc6d-38e143a44837" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_ac1021c0-6ebb-4689-a58e-15485da186f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_UnidentifiedThirdPartiesMember_e84112dd-7980-4423-bfc5-af6bdcf55836" xlink:href="wlkp-20240930.xsd#wlkp_UnidentifiedThirdPartiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_ac1021c0-6ebb-4689-a58e-15485da186f7" xlink:to="loc_wlkp_UnidentifiedThirdPartiesMember_e84112dd-7980-4423-bfc5-af6bdcf55836" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_2c85245a-2213-4d15-abc7-c22955ad83ed" xlink:href="wlkp-20240930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_ac1021c0-6ebb-4689-a58e-15485da186f7" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_2c85245a-2213-4d15-abc7-c22955ad83ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountUnitsIssued_7dcfa754-6340-4ef9-87df-1cd46703aeb7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountUnitsIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_99b14fab-22b2-41fe-8a85-c5fe48e27885" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountUnitsIssued_7dcfa754-6340-4ef9-87df-1cd46703aeb7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding_66a3721b-4726-444f-b4fa-1e4a0e3e6ee8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_99b14fab-22b2-41fe-8a85-c5fe48e27885" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding_66a3721b-4726-444f-b4fa-1e4a0e3e6ee8" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/ConsolidatedStatementsofOperations" xlink:type="simple" xlink:href="wlkp-20240930.xsd#ConsolidatedStatementsofOperations"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/ConsolidatedStatementsofOperations" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_d712cb94-8370-4006-960c-e6124e74473a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_b41ba2c1-32f5-4974-9cba-cac3c3ebeb6c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_d712cb94-8370-4006-960c-e6124e74473a" xlink:to="loc_us-gaap_StatementTable_b41ba2c1-32f5-4974-9cba-cac3c3ebeb6c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_0e110db4-3dc7-4797-a164-56de3943d4b4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_b41ba2c1-32f5-4974-9cba-cac3c3ebeb6c" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_0e110db4-3dc7-4797-a164-56de3943d4b4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_0e110db4-3dc7-4797-a164-56de3943d4b4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_0e110db4-3dc7-4797-a164-56de3943d4b4" xlink:to="loc_us-gaap_RelatedPartyDomain_0e110db4-3dc7-4797-a164-56de3943d4b4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_2cf02fed-7ca4-4d9b-a512-5801da00b27b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_0e110db4-3dc7-4797-a164-56de3943d4b4" xlink:to="loc_us-gaap_RelatedPartyDomain_2cf02fed-7ca4-4d9b-a512-5801da00b27b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_86f16c33-d27b-4a04-8544-f728b3218808" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_2cf02fed-7ca4-4d9b-a512-5801da00b27b" xlink:to="loc_srt_AffiliatedEntityMember_86f16c33-d27b-4a04-8544-f728b3218808" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonrelatedPartyMember_e420c16e-f45e-45eb-83c4-576905310b88" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NonrelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_2cf02fed-7ca4-4d9b-a512-5801da00b27b" xlink:to="loc_us-gaap_NonrelatedPartyMember_e420c16e-f45e-45eb-83c4-576905310b88" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_65e14b74-d46c-4967-a3d6-8d075e1c58f5" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_b41ba2c1-32f5-4974-9cba-cac3c3ebeb6c" xlink:to="loc_srt_CounterpartyNameAxis_65e14b74-d46c-4967-a3d6-8d075e1c58f5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_65e14b74-d46c-4967-a3d6-8d075e1c58f5_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_65e14b74-d46c-4967-a3d6-8d075e1c58f5" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_65e14b74-d46c-4967-a3d6-8d075e1c58f5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_9584cb6b-d4e0-42bc-ba52-f67f9e5772db" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_65e14b74-d46c-4967-a3d6-8d075e1c58f5" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_9584cb6b-d4e0-42bc-ba52-f67f9e5772db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_8ea65a75-ba56-4db7-8ed9-52c9e76ae66d" xlink:href="wlkp-20240930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_9584cb6b-d4e0-42bc-ba52-f67f9e5772db" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_8ea65a75-ba56-4db7-8ed9-52c9e76ae66d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_UnidentifiedThirdPartiesMember_a866c0da-0937-4519-9624-ee5612792155" xlink:href="wlkp-20240930.xsd#wlkp_UnidentifiedThirdPartiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_9584cb6b-d4e0-42bc-ba52-f67f9e5772db" xlink:to="loc_wlkp_UnidentifiedThirdPartiesMember_a866c0da-0937-4519-9624-ee5612792155" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_e2e1b49f-b5e2-44a8-be20-62f04f94be65" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_b41ba2c1-32f5-4974-9cba-cac3c3ebeb6c" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_e2e1b49f-b5e2-44a8-be20-62f04f94be65" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_e2e1b49f-b5e2-44a8-be20-62f04f94be65_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_e2e1b49f-b5e2-44a8-be20-62f04f94be65" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_e2e1b49f-b5e2-44a8-be20-62f04f94be65_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_f7c4f840-a583-4bf0-aa80-0395d5421a87" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_e2e1b49f-b5e2-44a8-be20-62f04f94be65" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_f7c4f840-a583-4bf0-aa80-0395d5421a87" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CommonUnitsMember_b97ba4cd-f55c-4fcb-8bd1-e44bdcc2492e" xlink:href="wlkp-20240930.xsd#wlkp_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_f7c4f840-a583-4bf0-aa80-0395d5421a87" xlink:to="loc_wlkp_CommonUnitsMember_b97ba4cd-f55c-4fcb-8bd1-e44bdcc2492e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_011df279-8997-4848-9a06-b8be5fa77969" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_b41ba2c1-32f5-4974-9cba-cac3c3ebeb6c" xlink:to="loc_srt_ConsolidatedEntitiesAxis_011df279-8997-4848-9a06-b8be5fa77969" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_011df279-8997-4848-9a06-b8be5fa77969_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_011df279-8997-4848-9a06-b8be5fa77969" xlink:to="loc_srt_ConsolidatedEntitiesDomain_011df279-8997-4848-9a06-b8be5fa77969_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_ac948bd1-243d-49f7-9ad9-165acc0dc820" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_011df279-8997-4848-9a06-b8be5fa77969" xlink:to="loc_srt_ConsolidatedEntitiesDomain_ac948bd1-243d-49f7-9ad9-165acc0dc820" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ParentCompanyMember_950ac775-3ea9-4ce1-b7b1-28539f4a2494" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ParentCompanyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_ac948bd1-243d-49f7-9ad9-165acc0dc820" xlink:to="loc_srt_ParentCompanyMember_950ac775-3ea9-4ce1-b7b1-28539f4a2494" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_62618100-be4e-4c51-b604-223d8a33ac32" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d712cb94-8370-4006-960c-e6124e74473a" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_62618100-be4e-4c51-b604-223d8a33ac32" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_583bb8de-496e-4e4b-a09b-d32e5a142d96" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d712cb94-8370-4006-960c-e6124e74473a" xlink:to="loc_us-gaap_Revenues_583bb8de-496e-4e4b-a09b-d32e5a142d96" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_25ea41a9-b5be-4107-9c11-046baf2ca710" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d712cb94-8370-4006-960c-e6124e74473a" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_25ea41a9-b5be-4107-9c11-046baf2ca710" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_1c08573c-ffd8-4dd9-a02e-0603f95862bb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GrossProfit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d712cb94-8370-4006-960c-e6124e74473a" xlink:to="loc_us-gaap_GrossProfit_1c08573c-ffd8-4dd9-a02e-0603f95862bb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_5279734b-5f71-4168-9a7f-f7fa033d2a01" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d712cb94-8370-4006-960c-e6124e74473a" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_5279734b-5f71-4168-9a7f-f7fa033d2a01" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_0e617b33-a6c1-4a26-852f-353a3cecc7de" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d712cb94-8370-4006-960c-e6124e74473a" xlink:to="loc_us-gaap_OperatingIncomeLoss_0e617b33-a6c1-4a26-852f-353a3cecc7de" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpenseAbstract_760f8319-2bb3-4e03-8fc7-3be0e9df753f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NonoperatingIncomeExpenseAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d712cb94-8370-4006-960c-e6124e74473a" xlink:to="loc_us-gaap_NonoperatingIncomeExpenseAbstract_760f8319-2bb3-4e03-8fc7-3be0e9df753f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense_04f282cf-4cfa-4c27-9e3e-36166408f51b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_760f8319-2bb3-4e03-8fc7-3be0e9df753f" xlink:to="loc_us-gaap_InterestExpense_04f282cf-4cfa-4c27-9e3e-36166408f51b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_1a915e72-20e2-4476-8082-203549e66da9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_760f8319-2bb3-4e03-8fc7-3be0e9df753f" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_1a915e72-20e2-4476-8082-203549e66da9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_8136665b-d0da-4c10-a485-830ee93f7bf2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d712cb94-8370-4006-960c-e6124e74473a" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_8136665b-d0da-4c10-a485-830ee93f7bf2" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_ceb053a3-bfd6-4ab1-9148-41a705e51ff0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d712cb94-8370-4006-960c-e6124e74473a" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_ceb053a3-bfd6-4ab1-9148-41a705e51ff0" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_b87bca48-8668-4bc4-8c03-55a10a720ce3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d712cb94-8370-4006-960c-e6124e74473a" xlink:to="loc_us-gaap_ProfitLoss_b87bca48-8668-4bc4-8c03-55a10a720ce3" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_04437fb5-b8be-4285-91f6-4f81e61c73a6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d712cb94-8370-4006-960c-e6124e74473a" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_04437fb5-b8be-4285-91f6-4f81e61c73a6" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_b48ef612-1733-4e93-8c76-1b3b094b1f66" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d712cb94-8370-4006-960c-e6124e74473a" xlink:to="loc_us-gaap_NetIncomeLoss_b48ef612-1733-4e93-8c76-1b3b094b1f66" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerUnitAbstract_287e08aa-549c-42f4-9da3-f9824768bd9a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EarningsPerUnitAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d712cb94-8370-4006-960c-e6124e74473a" xlink:to="loc_us-gaap_EarningsPerUnitAbstract_287e08aa-549c-42f4-9da3-f9824768bd9a" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax_2026e99c-03fd-4487-9d3c-009570de3c2e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerUnitAbstract_287e08aa-549c-42f4-9da3-f9824768bd9a" xlink:to="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax_2026e99c-03fd-4487-9d3c-009570de3c2e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted_eccf4595-ed7f-41db-ad61-78eedd164beb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerUnitAbstract_287e08aa-549c-42f4-9da3-f9824768bd9a" xlink:to="loc_us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted_eccf4595-ed7f-41db-ad61-78eedd164beb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfLimitedPartnershipAndGeneralPartnershipUnitOutstandingBasicAndDiluted_663249a5-d8a6-4a57-acec-e3ce3dfda05b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_WeightedAverageNumberOfLimitedPartnershipAndGeneralPartnershipUnitOutstandingBasicAndDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d712cb94-8370-4006-960c-e6124e74473a" xlink:to="loc_us-gaap_WeightedAverageNumberOfLimitedPartnershipAndGeneralPartnershipUnitOutstandingBasicAndDiluted_663249a5-d8a6-4a57-acec-e3ce3dfda05b" xlink:type="arc" order="13"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/ConsolidatedStatementsofChangesinEquity" xlink:type="simple" xlink:href="wlkp-20240930.xsd#ConsolidatedStatementsofChangesinEquity"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/ConsolidatedStatementsofChangesinEquity" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_cec62fdb-ee76-4171-abd6-cec77d692bed" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_6e41b7ac-06bf-436b-82c3-f8df099b4d85" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_cec62fdb-ee76-4171-abd6-cec77d692bed" xlink:to="loc_us-gaap_StatementTable_6e41b7ac-06bf-436b-82c3-f8df099b4d85" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_a10b1720-ab0d-4949-a7af-1a8d2682e0b4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_6e41b7ac-06bf-436b-82c3-f8df099b4d85" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_a10b1720-ab0d-4949-a7af-1a8d2682e0b4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_a10b1720-ab0d-4949-a7af-1a8d2682e0b4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_a10b1720-ab0d-4949-a7af-1a8d2682e0b4" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_a10b1720-ab0d-4949-a7af-1a8d2682e0b4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_73e19ddf-c8af-4360-8651-246def24d84c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_a10b1720-ab0d-4949-a7af-1a8d2682e0b4" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_73e19ddf-c8af-4360-8651-246def24d84c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CommonUnitsMember_061206d7-262d-4c7f-914f-55d1392d19a9" xlink:href="wlkp-20240930.xsd#wlkp_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_73e19ddf-c8af-4360-8651-246def24d84c" xlink:to="loc_wlkp_CommonUnitsMember_061206d7-262d-4c7f-914f-55d1392d19a9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_993f487e-6442-43d9-8ec1-d892c8090a0c" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_6e41b7ac-06bf-436b-82c3-f8df099b4d85" xlink:to="loc_srt_CounterpartyNameAxis_993f487e-6442-43d9-8ec1-d892c8090a0c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_993f487e-6442-43d9-8ec1-d892c8090a0c_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_993f487e-6442-43d9-8ec1-d892c8090a0c" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_993f487e-6442-43d9-8ec1-d892c8090a0c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_4ade647b-1033-4a11-a5a9-3429b44ebd94" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_993f487e-6442-43d9-8ec1-d892c8090a0c" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_4ade647b-1033-4a11-a5a9-3429b44ebd94" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_UnidentifiedThirdPartiesMember_0cf62da9-dc3d-4160-914c-b0faac3352e8" xlink:href="wlkp-20240930.xsd#wlkp_UnidentifiedThirdPartiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_4ade647b-1033-4a11-a5a9-3429b44ebd94" xlink:to="loc_wlkp_UnidentifiedThirdPartiesMember_0cf62da9-dc3d-4160-914c-b0faac3352e8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_cde319ef-211f-4fbd-bd89-91cac9d0a027" xlink:href="wlkp-20240930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_4ade647b-1033-4a11-a5a9-3429b44ebd94" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_cde319ef-211f-4fbd-bd89-91cac9d0a027" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_a7f898b1-d375-4328-8733-dfe4dae5e915" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_6e41b7ac-06bf-436b-82c3-f8df099b4d85" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_a7f898b1-d375-4328-8733-dfe4dae5e915" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_a7f898b1-d375-4328-8733-dfe4dae5e915_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_a7f898b1-d375-4328-8733-dfe4dae5e915" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_a7f898b1-d375-4328-8733-dfe4dae5e915_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_2543063b-6b84-4740-a461-b9452f8d0650" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_a7f898b1-d375-4328-8733-dfe4dae5e915" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_2543063b-6b84-4740-a461-b9452f8d0650" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnerMember_275899d3-4e36-4d5e-976a-0416dfe0ed03" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_2543063b-6b84-4740-a461-b9452f8d0650" xlink:to="loc_us-gaap_LimitedPartnerMember_275899d3-4e36-4d5e-976a-0416dfe0ed03" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralPartnerMember_a985ed08-60e4-42e5-a999-53d3af7c7781" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GeneralPartnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_2543063b-6b84-4740-a461-b9452f8d0650" xlink:to="loc_us-gaap_GeneralPartnerMember_a985ed08-60e4-42e5-a999-53d3af7c7781" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_60fe88d8-37ca-431a-afd0-830ff46146ad" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_6e41b7ac-06bf-436b-82c3-f8df099b4d85" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_60fe88d8-37ca-431a-afd0-830ff46146ad" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_60fe88d8-37ca-431a-afd0-830ff46146ad_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_60fe88d8-37ca-431a-afd0-830ff46146ad" xlink:to="loc_us-gaap_EquityComponentDomain_60fe88d8-37ca-431a-afd0-830ff46146ad_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_d385a74d-4397-446c-a172-7e9346724afb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_60fe88d8-37ca-431a-afd0-830ff46146ad" xlink:to="loc_us-gaap_EquityComponentDomain_d385a74d-4397-446c-a172-7e9346724afb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_e53cd656-cd2e-4278-b31c-9adbd37e30ca" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_d385a74d-4397-446c-a172-7e9346724afb" xlink:to="loc_us-gaap_NoncontrollingInterestMember_e53cd656-cd2e-4278-b31c-9adbd37e30ca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_bcba032c-322d-4439-8371-94cf60e813c2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_cec62fdb-ee76-4171-abd6-cec77d692bed" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_bcba032c-322d-4439-8371-94cf60e813c2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_ac25bdc3-eb1b-45f9-a0a7-d3dbd4276463" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_bcba032c-322d-4439-8371-94cf60e813c2" xlink:to="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_ac25bdc3-eb1b-45f9-a0a7-d3dbd4276463" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_c1d875e9-f444-43a2-86d7-23309a956216" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_bcba032c-322d-4439-8371-94cf60e813c2" xlink:to="loc_us-gaap_ProfitLoss_c1d875e9-f444-43a2-86d7-23309a956216" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueOther_199e1a5f-976c-414e-a7b2-2a4d7db2581a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodValueOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_bcba032c-322d-4439-8371-94cf60e813c2" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueOther_199e1a5f-976c-414e-a7b2-2a4d7db2581a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountDistributionAmount_5355d3bb-e959-45f4-89f7-97e94fc0f5c3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountDistributionAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_bcba032c-322d-4439-8371-94cf60e813c2" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountDistributionAmount_5355d3bb-e959-45f4-89f7-97e94fc0f5c3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_0a5fac69-71fc-4440-8cb1-864b295d156d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_bcba032c-322d-4439-8371-94cf60e813c2" xlink:to="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_0a5fac69-71fc-4440-8cb1-864b295d156d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_cfed1fa5-786b-4d55-9c7a-a197bf1fe94b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/DescriptionofBusinessandBasisofPresentationDetails" xlink:type="simple" xlink:href="wlkp-20240930.xsd#DescriptionofBusinessandBasisofPresentationDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/DescriptionofBusinessandBasisofPresentationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_17060e69-c67e-4eff-9c9c-369b023ebe65" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_2e4bf810-d6e2-45b1-9d8e-977767cf9b04" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_17060e69-c67e-4eff-9c9c-369b023ebe65" xlink:to="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_2e4bf810-d6e2-45b1-9d8e-977767cf9b04" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_a700abba-47a4-4340-91c6-7a61868d4329" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_2e4bf810-d6e2-45b1-9d8e-977767cf9b04" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_a700abba-47a4-4340-91c6-7a61868d4329" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_a700abba-47a4-4340-91c6-7a61868d4329_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_a700abba-47a4-4340-91c6-7a61868d4329" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_a700abba-47a4-4340-91c6-7a61868d4329_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_3b2f33a9-9829-4c9d-82ee-2d14ba7269c5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_a700abba-47a4-4340-91c6-7a61868d4329" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_3b2f33a9-9829-4c9d-82ee-2d14ba7269c5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnerMember_bc66fd94-2a28-44ee-b651-3291c2912477" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_3b2f33a9-9829-4c9d-82ee-2d14ba7269c5" xlink:to="loc_us-gaap_LimitedPartnerMember_bc66fd94-2a28-44ee-b651-3291c2912477" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_d4fa7a37-9ba0-404e-aa3a-0a213e31d2c0" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_2e4bf810-d6e2-45b1-9d8e-977767cf9b04" xlink:to="loc_srt_OwnershipAxis_d4fa7a37-9ba0-404e-aa3a-0a213e31d2c0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_d4fa7a37-9ba0-404e-aa3a-0a213e31d2c0_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_d4fa7a37-9ba0-404e-aa3a-0a213e31d2c0" xlink:to="loc_srt_OwnershipDomain_d4fa7a37-9ba0-404e-aa3a-0a213e31d2c0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_f6ee7786-b324-4594-a99c-68a9b57d3e50" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_d4fa7a37-9ba0-404e-aa3a-0a213e31d2c0" xlink:to="loc_srt_OwnershipDomain_f6ee7786-b324-4594-a99c-68a9b57d3e50" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_72713574-ea69-498c-b13e-7ccc29a99aca" xlink:href="wlkp-20240930.xsd#wlkp_WestlakeChemicalOpCoLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_f6ee7786-b324-4594-a99c-68a9b57d3e50" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_72713574-ea69-498c-b13e-7ccc29a99aca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_WestlakeChemicalOpCoGPLLCMember_ee2e587b-0ba6-42e2-9d00-f6b500622e7b" xlink:href="wlkp-20240930.xsd#wlkp_WestlakeChemicalOpCoGPLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_f6ee7786-b324-4594-a99c-68a9b57d3e50" xlink:to="loc_wlkp_WestlakeChemicalOpCoGPLLCMember_ee2e587b-0ba6-42e2-9d00-f6b500622e7b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_94ea25f4-1750-4fdd-a0c0-b09d655d1729" xlink:href="wlkp-20240930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_f6ee7786-b324-4594-a99c-68a9b57d3e50" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_94ea25f4-1750-4fdd-a0c0-b09d655d1729" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_0599c703-707d-4b61-976f-6c4ef803c1fc" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_2e4bf810-d6e2-45b1-9d8e-977767cf9b04" xlink:to="loc_dei_LegalEntityAxis_0599c703-707d-4b61-976f-6c4ef803c1fc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_0599c703-707d-4b61-976f-6c4ef803c1fc_default" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_0599c703-707d-4b61-976f-6c4ef803c1fc" xlink:to="loc_dei_EntityDomain_0599c703-707d-4b61-976f-6c4ef803c1fc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_01fc85fb-6b42-4f36-9542-ed5416909ea6" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_0599c703-707d-4b61-976f-6c4ef803c1fc" xlink:to="loc_dei_EntityDomain_01fc85fb-6b42-4f36-9542-ed5416909ea6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_58f88718-5995-4807-9ab5-3642f57acc3d" xlink:href="wlkp-20240930.xsd#wlkp_WestlakeChemicalOpCoLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_01fc85fb-6b42-4f36-9542-ed5416909ea6" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_58f88718-5995-4807-9ab5-3642f57acc3d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_bad82dd2-e9f3-402c-ba91-2bd4fdb2379c" xlink:href="wlkp-20240930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_01fc85fb-6b42-4f36-9542-ed5416909ea6" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_bad82dd2-e9f3-402c-ba91-2bd4fdb2379c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_71450945-996b-4fa9-b5be-2ab2c0802cd6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_2e4bf810-d6e2-45b1-9d8e-977767cf9b04" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_71450945-996b-4fa9-b5be-2ab2c0802cd6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_71450945-996b-4fa9-b5be-2ab2c0802cd6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_71450945-996b-4fa9-b5be-2ab2c0802cd6" xlink:to="loc_us-gaap_RelatedPartyDomain_71450945-996b-4fa9-b5be-2ab2c0802cd6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_28b56d56-a180-4a49-890b-df2841f9d373" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_71450945-996b-4fa9-b5be-2ab2c0802cd6" xlink:to="loc_us-gaap_RelatedPartyDomain_28b56d56-a180-4a49-890b-df2841f9d373" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_23f939bd-3955-4438-bed7-a7689579a745" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_28b56d56-a180-4a49-890b-df2841f9d373" xlink:to="loc_srt_AffiliatedEntityMember_23f939bd-3955-4438-bed7-a7689579a745" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedLiabilityCompanyMember_987ae2f1-289c-4496-8e5f-835ffdadd48a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedLiabilityCompanyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_28b56d56-a180-4a49-890b-df2841f9d373" xlink:to="loc_us-gaap_LimitedLiabilityCompanyMember_987ae2f1-289c-4496-8e5f-835ffdadd48a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MajorityOwnedSubsidiaryUnconsolidatedMember_6b864fd3-f8e5-4dd1-8112-98b4ca61db8d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_MajorityOwnedSubsidiaryUnconsolidatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_28b56d56-a180-4a49-890b-df2841f9d373" xlink:to="loc_us-gaap_MajorityOwnedSubsidiaryUnconsolidatedMember_6b864fd3-f8e5-4dd1-8112-98b4ca61db8d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountUnitsSoldInPublicOffering_ea38a74f-c074-4145-a4c4-08e01cdb5f8d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnersCapitalAccountUnitsSoldInPublicOffering"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_17060e69-c67e-4eff-9c9c-369b023ebe65" xlink:to="loc_us-gaap_PartnersCapitalAccountUnitsSoldInPublicOffering_ea38a74f-c074-4145-a4c4-08e01cdb5f8d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest_8ba19cd2-538e-4fd2-ace4-c79f245632fa" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_17060e69-c67e-4eff-9c9c-369b023ebe65" xlink:to="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest_8ba19cd2-538e-4fd2-ace4-c79f245632fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_NumberofProductionFacilities_e254d5ce-718e-4b08-9b9f-da2bf1ad19bd" xlink:href="wlkp-20240930.xsd#wlkp_NumberofProductionFacilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_17060e69-c67e-4eff-9c9c-369b023ebe65" xlink:to="loc_wlkp_NumberofProductionFacilities_e254d5ce-718e-4b08-9b9f-da2bf1ad19bd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_NumberOfCommonCarrierPipelines_0853bb21-356d-413e-b9d6-fff029a5becd" xlink:href="wlkp-20240930.xsd#wlkp_NumberOfCommonCarrierPipelines"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_17060e69-c67e-4eff-9c9c-369b023ebe65" xlink:to="loc_wlkp_NumberOfCommonCarrierPipelines_0853bb21-356d-413e-b9d6-fff029a5becd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersAdditionalOwnershipInterest_4d4ec2b4-fd0e-4575-93b5-99b48d000557" xlink:href="wlkp-20240930.xsd#wlkp_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersAdditionalOwnershipInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_17060e69-c67e-4eff-9c9c-369b023ebe65" xlink:to="loc_wlkp_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersAdditionalOwnershipInterest_4d4ec2b4-fd0e-4575-93b5-99b48d000557" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_adae039c-abca-40f3-adf5-85829a319ad7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PaymentsToAcquireLimitedPartnershipInterests"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_17060e69-c67e-4eff-9c9c-369b023ebe65" xlink:to="loc_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_adae039c-abca-40f3-adf5-85829a319ad7" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnitBasicandDilutedIncomePerLimitedPartnerUnitDetails" xlink:type="simple" xlink:href="wlkp-20240930.xsd#DistributionsandNetIncomePerLimitedPartnerUnitBasicandDilutedIncomePerLimitedPartnerUnitDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnitBasicandDilutedIncomePerLimitedPartnerUnitDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_30839a16-f409-49f9-8983-19e4cdbe36e9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_1cbcdada-0a27-45c7-be3c-d2d4e5e3e1be" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_30839a16-f409-49f9-8983-19e4cdbe36e9" xlink:to="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_1cbcdada-0a27-45c7-be3c-d2d4e5e3e1be" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_a52da614-8c9a-4d57-9dae-db6fd13389e6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_1cbcdada-0a27-45c7-be3c-d2d4e5e3e1be" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_a52da614-8c9a-4d57-9dae-db6fd13389e6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_a52da614-8c9a-4d57-9dae-db6fd13389e6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_a52da614-8c9a-4d57-9dae-db6fd13389e6" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_a52da614-8c9a-4d57-9dae-db6fd13389e6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_ea4aae03-c127-4e72-a237-64d776100789" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_a52da614-8c9a-4d57-9dae-db6fd13389e6" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_ea4aae03-c127-4e72-a237-64d776100789" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CommonUnitsMember_4be66683-2f0f-46ce-9f4b-c87e838449dd" xlink:href="wlkp-20240930.xsd#wlkp_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_ea4aae03-c127-4e72-a237-64d776100789" xlink:to="loc_wlkp_CommonUnitsMember_4be66683-2f0f-46ce-9f4b-c87e838449dd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_eb97135b-0d21-40fd-8c90-45ef5d1be345" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_1cbcdada-0a27-45c7-be3c-d2d4e5e3e1be" xlink:to="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_eb97135b-0d21-40fd-8c90-45ef5d1be345" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_eb97135b-0d21-40fd-8c90-45ef5d1be345_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncentiveDistributionRecipientDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_eb97135b-0d21-40fd-8c90-45ef5d1be345" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_eb97135b-0d21-40fd-8c90-45ef5d1be345_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_b2e85a05-ad9a-403f-ba7f-3f67d7a1646f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncentiveDistributionRecipientDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_eb97135b-0d21-40fd-8c90-45ef5d1be345" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_b2e85a05-ad9a-403f-ba7f-3f67d7a1646f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_IDRHoldersMember_bbf6725e-f0b4-4d02-a615-6405d5128353" xlink:href="wlkp-20240930.xsd#wlkp_IDRHoldersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncentiveDistributionRecipientDomain_b2e85a05-ad9a-403f-ba7f-3f67d7a1646f" xlink:to="loc_wlkp_IDRHoldersMember_bbf6725e-f0b4-4d02-a615-6405d5128353" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_4c52e28f-347b-4bcb-8481-c3d64d5aaa58" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_1cbcdada-0a27-45c7-be3c-d2d4e5e3e1be" xlink:to="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_4c52e28f-347b-4bcb-8481-c3d64d5aaa58" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionTypeDomain_4c52e28f-347b-4bcb-8481-c3d64d5aaa58_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DistributionTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_4c52e28f-347b-4bcb-8481-c3d64d5aaa58" xlink:to="loc_us-gaap_DistributionTypeDomain_4c52e28f-347b-4bcb-8481-c3d64d5aaa58_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionTypeDomain_4d7d2147-07c4-46fe-8b59-4d4fbacb0acc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DistributionTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_4c52e28f-347b-4bcb-8481-c3d64d5aaa58" xlink:to="loc_us-gaap_DistributionTypeDomain_4d7d2147-07c4-46fe-8b59-4d4fbacb0acc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashDistributionMember_9663c82a-3f21-451d-95ba-ec2863933f66" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CashDistributionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionTypeDomain_4d7d2147-07c4-46fe-8b59-4d4fbacb0acc" xlink:to="loc_us-gaap_CashDistributionMember_9663c82a-3f21-451d-95ba-ec2863933f66" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_1e134288-40b6-41a6-842d-7457dbdfc852" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_30839a16-f409-49f9-8983-19e4cdbe36e9" xlink:to="loc_us-gaap_NetIncomeLoss_1e134288-40b6-41a6-842d-7457dbdfc852" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributedEarnings_508a08c5-1c78-4068-a13e-635a9ede4447" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DistributedEarnings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_30839a16-f409-49f9-8983-19e4cdbe36e9" xlink:to="loc_us-gaap_DistributedEarnings_508a08c5-1c78-4068-a13e-635a9ede4447" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UndistributedEarnings_b5041a03-0946-4b79-81ef-1e6c36086764" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_UndistributedEarnings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_30839a16-f409-49f9-8983-19e4cdbe36e9" xlink:to="loc_us-gaap_UndistributedEarnings_b5041a03-0946-4b79-81ef-1e6c36086764" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_IncentiveDistributionSubsequentDistributionAmount_dc26f5ae-fa15-4c18-923d-ce693067ed35" xlink:href="wlkp-20240930.xsd#wlkp_IncentiveDistributionSubsequentDistributionAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_30839a16-f409-49f9-8983-19e4cdbe36e9" xlink:to="loc_wlkp_IncentiveDistributionSubsequentDistributionAmount_dc26f5ae-fa15-4c18-923d-ce693067ed35" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_EarningsPerUnitBasicAndDilutedOtherDisclosureAbstract_1257e734-c3e9-4fc3-aa8e-d9aec3470911" xlink:href="wlkp-20240930.xsd#wlkp_EarningsPerUnitBasicAndDilutedOtherDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_30839a16-f409-49f9-8983-19e4cdbe36e9" xlink:to="loc_wlkp_EarningsPerUnitBasicAndDilutedOtherDisclosureAbstract_1257e734-c3e9-4fc3-aa8e-d9aec3470911" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfLimitedPartnershipAndGeneralPartnershipUnitOutstandingBasicAndDiluted_d8e32a94-6085-462b-b45b-a9a13bf7bc03" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_WeightedAverageNumberOfLimitedPartnershipAndGeneralPartnershipUnitOutstandingBasicAndDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_EarningsPerUnitBasicAndDilutedOtherDisclosureAbstract_1257e734-c3e9-4fc3-aa8e-d9aec3470911" xlink:to="loc_us-gaap_WeightedAverageNumberOfLimitedPartnershipAndGeneralPartnershipUnitOutstandingBasicAndDiluted_d8e32a94-6085-462b-b45b-a9a13bf7bc03" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasicAbstract_78c74167-442c-435d-9df6-692cb13bc4ec" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EarningsPerShareBasicAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_30839a16-f409-49f9-8983-19e4cdbe36e9" xlink:to="loc_us-gaap_EarningsPerShareBasicAbstract_78c74167-442c-435d-9df6-692cb13bc4ec" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax_25661ea8-9e59-45a3-845f-f6b1f96f4f94" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_78c74167-442c-435d-9df6-692cb13bc4ec" xlink:to="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax_25661ea8-9e59-45a3-845f-f6b1f96f4f94" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted_88ade298-8e45-4ad0-be76-72efbe637848" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_78c74167-442c-435d-9df6-692cb13bc4ec" xlink:to="loc_us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted_88ade298-8e45-4ad0-be76-72efbe637848" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnitDistributionsDeclaredDetails" xlink:type="simple" xlink:href="wlkp-20240930.xsd#DistributionsandNetIncomePerLimitedPartnerUnitDistributionsDeclaredDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnitDistributionsDeclaredDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_021afbf5-6312-4183-a8f8-cd489866fec0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DistributionMadeToLimitedPartnerLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_50941d50-ec96-4ba4-8764-4f8569a94fd7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DistributionsMadeToLimitedPartnerTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_021afbf5-6312-4183-a8f8-cd489866fec0" xlink:to="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_50941d50-ec96-4ba4-8764-4f8569a94fd7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_95aca2b6-e9a4-4377-8c10-9d3bd3b9421f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_50941d50-ec96-4ba4-8764-4f8569a94fd7" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_95aca2b6-e9a4-4377-8c10-9d3bd3b9421f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_95aca2b6-e9a4-4377-8c10-9d3bd3b9421f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_95aca2b6-e9a4-4377-8c10-9d3bd3b9421f" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_95aca2b6-e9a4-4377-8c10-9d3bd3b9421f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_35ded01c-b0cb-480e-b42e-b88ed4f2ec69" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_95aca2b6-e9a4-4377-8c10-9d3bd3b9421f" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_35ded01c-b0cb-480e-b42e-b88ed4f2ec69" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_cbb35708-7141-4047-a06e-32cf27153e7d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_35ded01c-b0cb-480e-b42e-b88ed4f2ec69" xlink:to="loc_us-gaap_SubsequentEventMember_cbb35708-7141-4047-a06e-32cf27153e7d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_a246aeda-1d7a-45e5-874e-5b0b132f3483" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_50941d50-ec96-4ba4-8764-4f8569a94fd7" xlink:to="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_a246aeda-1d7a-45e5-874e-5b0b132f3483" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionTypeDomain_a246aeda-1d7a-45e5-874e-5b0b132f3483_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DistributionTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_a246aeda-1d7a-45e5-874e-5b0b132f3483" xlink:to="loc_us-gaap_DistributionTypeDomain_a246aeda-1d7a-45e5-874e-5b0b132f3483_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionTypeDomain_6cb1b45d-37bf-45af-ba49-ff6b72b37936" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DistributionTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_a246aeda-1d7a-45e5-874e-5b0b132f3483" xlink:to="loc_us-gaap_DistributionTypeDomain_6cb1b45d-37bf-45af-ba49-ff6b72b37936" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashDistributionMember_b46ebf48-2963-4335-a533-5aa042f91dca" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CashDistributionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionTypeDomain_6cb1b45d-37bf-45af-ba49-ff6b72b37936" xlink:to="loc_us-gaap_CashDistributionMember_b46ebf48-2963-4335-a533-5aa042f91dca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CashDistributionTrancheOneMember_4ed211b2-d198-4523-9343-45178ba038ec" xlink:href="wlkp-20240930.xsd#wlkp_CashDistributionTrancheOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashDistributionMember_b46ebf48-2963-4335-a533-5aa042f91dca" xlink:to="loc_wlkp_CashDistributionTrancheOneMember_4ed211b2-d198-4523-9343-45178ba038ec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CashDistributionTrancheTwoMember_b6aa2091-8b42-4fc7-b311-42bb8c699fc0" xlink:href="wlkp-20240930.xsd#wlkp_CashDistributionTrancheTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashDistributionMember_b46ebf48-2963-4335-a533-5aa042f91dca" xlink:to="loc_wlkp_CashDistributionTrancheTwoMember_b6aa2091-8b42-4fc7-b311-42bb8c699fc0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CashDistributionTrancheThreeMember_6d6f32eb-b002-42d8-a0b5-841f886ba448" xlink:href="wlkp-20240930.xsd#wlkp_CashDistributionTrancheThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashDistributionMember_b46ebf48-2963-4335-a533-5aa042f91dca" xlink:to="loc_wlkp_CashDistributionTrancheThreeMember_6d6f32eb-b002-42d8-a0b5-841f886ba448" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_b78d7b4b-e748-45cc-806e-56ead4f391e6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_50941d50-ec96-4ba4-8764-4f8569a94fd7" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_b78d7b4b-e748-45cc-806e-56ead4f391e6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_b78d7b4b-e748-45cc-806e-56ead4f391e6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_b78d7b4b-e748-45cc-806e-56ead4f391e6" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_b78d7b4b-e748-45cc-806e-56ead4f391e6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_02b7471b-78e4-4505-918a-87c79d98baa2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_b78d7b4b-e748-45cc-806e-56ead4f391e6" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_02b7471b-78e4-4505-918a-87c79d98baa2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CommonUnitsMember_2410214f-9c49-4d3a-92ef-119923ebd059" xlink:href="wlkp-20240930.xsd#wlkp_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_02b7471b-78e4-4505-918a-87c79d98baa2" xlink:to="loc_wlkp_CommonUnitsMember_2410214f-9c49-4d3a-92ef-119923ebd059" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_ddf78b84-25f6-48af-9199-da5f3c3cc7d2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_50941d50-ec96-4ba4-8764-4f8569a94fd7" xlink:to="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_ddf78b84-25f6-48af-9199-da5f3c3cc7d2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_ddf78b84-25f6-48af-9199-da5f3c3cc7d2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncentiveDistributionRecipientDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_ddf78b84-25f6-48af-9199-da5f3c3cc7d2" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_ddf78b84-25f6-48af-9199-da5f3c3cc7d2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_157245cc-b8c0-4a97-b73b-e9b1084ba5e5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncentiveDistributionRecipientDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_ddf78b84-25f6-48af-9199-da5f3c3cc7d2" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_157245cc-b8c0-4a97-b73b-e9b1084ba5e5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_UnitHoldersMember_a66c94c9-53dc-4dbc-ae92-a8c4724aabfb" xlink:href="wlkp-20240930.xsd#wlkp_UnitHoldersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncentiveDistributionRecipientDomain_157245cc-b8c0-4a97-b73b-e9b1084ba5e5" xlink:to="loc_wlkp_UnitHoldersMember_a66c94c9-53dc-4dbc-ae92-a8c4724aabfb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_IDRHoldersMember_f2a10469-1f65-4f47-9396-58d7a138ad97" xlink:href="wlkp-20240930.xsd#wlkp_IDRHoldersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncentiveDistributionRecipientDomain_157245cc-b8c0-4a97-b73b-e9b1084ba5e5" xlink:to="loc_wlkp_IDRHoldersMember_f2a10469-1f65-4f47-9396-58d7a138ad97" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_1f440b2f-ed86-42c3-bb47-a281077abaaf" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_50941d50-ec96-4ba4-8764-4f8569a94fd7" xlink:to="loc_srt_RangeAxis_1f440b2f-ed86-42c3-bb47-a281077abaaf" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_1f440b2f-ed86-42c3-bb47-a281077abaaf_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_1f440b2f-ed86-42c3-bb47-a281077abaaf" xlink:to="loc_srt_RangeMember_1f440b2f-ed86-42c3-bb47-a281077abaaf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_cf45f772-087b-4121-9b32-c9f8d81d8f5f" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_1f440b2f-ed86-42c3-bb47-a281077abaaf" xlink:to="loc_srt_RangeMember_cf45f772-087b-4121-9b32-c9f8d81d8f5f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_41f12d4f-2cd1-45ef-a9a9-2852d0407c55" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_cf45f772-087b-4121-9b32-c9f8d81d8f5f" xlink:to="loc_srt_MinimumMember_41f12d4f-2cd1-45ef-a9a9-2852d0407c55" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_776370f7-41fe-4688-a070-011af6691289" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_cf45f772-087b-4121-9b32-c9f8d81d8f5f" xlink:to="loc_srt_MaximumMember_776370f7-41fe-4688-a070-011af6691289" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit_735d828c-145f-4816-9467-fea4268b2109" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_021afbf5-6312-4183-a8f8-cd489866fec0" xlink:to="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit_735d828c-145f-4816-9467-fea4268b2109" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_IncentiveDistributionRightsTargetDistributionPerUnitRequiringMarginalPercentageDistributiontoIDRHolders_a667207e-4674-4b32-a3e3-a5e23ccbf0ab" xlink:href="wlkp-20240930.xsd#wlkp_IncentiveDistributionRightsTargetDistributionPerUnitRequiringMarginalPercentageDistributiontoIDRHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_021afbf5-6312-4183-a8f8-cd489866fec0" xlink:to="loc_wlkp_IncentiveDistributionRightsTargetDistributionPerUnitRequiringMarginalPercentageDistributiontoIDRHolders_a667207e-4674-4b32-a3e3-a5e23ccbf0ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_IncentiveDistributionMarginalPercentageInterestinDistributions_1b8e1418-24d1-4a3e-b34a-6a99a748512d" xlink:href="wlkp-20240930.xsd#wlkp_IncentiveDistributionMarginalPercentageInterestinDistributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_021afbf5-6312-4183-a8f8-cd489866fec0" xlink:to="loc_wlkp_IncentiveDistributionMarginalPercentageInterestinDistributions_1b8e1418-24d1-4a3e-b34a-6a99a748512d" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/PartnersEquityDetails" xlink:type="simple" xlink:href="wlkp-20240930.xsd#PartnersEquityDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/PartnersEquityDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_d3df98e8-0bce-4df3-9956-d3de8a5343fe" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_650be6a5-e3f9-453d-b85b-01ec9a21f2ad" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_d3df98e8-0bce-4df3-9956-d3de8a5343fe" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_650be6a5-e3f9-453d-b85b-01ec9a21f2ad" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_f5e223ec-741c-41d6-8718-8a500cd74daa" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_650be6a5-e3f9-453d-b85b-01ec9a21f2ad" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_f5e223ec-741c-41d6-8718-8a500cd74daa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_f5e223ec-741c-41d6-8718-8a500cd74daa_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_f5e223ec-741c-41d6-8718-8a500cd74daa" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_f5e223ec-741c-41d6-8718-8a500cd74daa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_15631f29-b057-4a15-b2a7-08a1eb7b4822" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_f5e223ec-741c-41d6-8718-8a500cd74daa" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_15631f29-b057-4a15-b2a7-08a1eb7b4822" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnerMember_29c4ceda-6f74-4d33-8b84-9891a62ba1e0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_15631f29-b057-4a15-b2a7-08a1eb7b4822" xlink:to="loc_us-gaap_LimitedPartnerMember_29c4ceda-6f74-4d33-8b84-9891a62ba1e0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_abd3dadc-78af-4d87-a45b-5f7778d7ac29" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_650be6a5-e3f9-453d-b85b-01ec9a21f2ad" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_abd3dadc-78af-4d87-a45b-5f7778d7ac29" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_abd3dadc-78af-4d87-a45b-5f7778d7ac29_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_abd3dadc-78af-4d87-a45b-5f7778d7ac29" xlink:to="loc_us-gaap_RelatedPartyDomain_abd3dadc-78af-4d87-a45b-5f7778d7ac29_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_c2c496be-63c0-4c0d-a8cc-4ce879f8e1b7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_abd3dadc-78af-4d87-a45b-5f7778d7ac29" xlink:to="loc_us-gaap_RelatedPartyDomain_c2c496be-63c0-4c0d-a8cc-4ce879f8e1b7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_905987a4-a613-4715-8ead-cf1e4f92ca1d" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_c2c496be-63c0-4c0d-a8cc-4ce879f8e1b7" xlink:to="loc_srt_AffiliatedEntityMember_905987a4-a613-4715-8ead-cf1e4f92ca1d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_PartnersUnitsMaximumAggregateOfferingAmountATM_8d37f045-1792-416c-9c18-2f80d6864ebb" xlink:href="wlkp-20240930.xsd#wlkp_PartnersUnitsMaximumAggregateOfferingAmountATM"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_d3df98e8-0bce-4df3-9956-d3de8a5343fe" xlink:to="loc_wlkp_PartnersUnitsMaximumAggregateOfferingAmountATM_8d37f045-1792-416c-9c18-2f80d6864ebb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountUnitsSoldInPublicOffering_325be702-a1b0-4c06-a590-70af689de180" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PartnersCapitalAccountUnitsSoldInPublicOffering"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_d3df98e8-0bce-4df3-9956-d3de8a5343fe" xlink:to="loc_us-gaap_PartnersCapitalAccountUnitsSoldInPublicOffering_325be702-a1b0-4c06-a590-70af689de180" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_PartnersCapitalAccountUnitsSoldinPublicOfferingPriceperUnit_2418d9bf-54ee-4d7d-b035-7ae18adb986c" xlink:href="wlkp-20240930.xsd#wlkp_PartnersCapitalAccountUnitsSoldinPublicOfferingPriceperUnit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_d3df98e8-0bce-4df3-9956-d3de8a5343fe" xlink:to="loc_wlkp_PartnersCapitalAccountUnitsSoldinPublicOfferingPriceperUnit_2418d9bf-54ee-4d7d-b035-7ae18adb986c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_PartnersCapitalAccountUnitsSoldtoRelatedParty_9bdc0633-0aba-44ca-bd4c-2669d8d31845" xlink:href="wlkp-20240930.xsd#wlkp_PartnersCapitalAccountUnitsSoldtoRelatedParty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_d3df98e8-0bce-4df3-9956-d3de8a5343fe" xlink:to="loc_wlkp_PartnersCapitalAccountUnitsSoldtoRelatedParty_9bdc0633-0aba-44ca-bd4c-2669d8d31845" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsSalestoRelatedPartiesDetails" xlink:type="simple" xlink:href="wlkp-20240930.xsd#RelatedPartyTransactionsSalestoRelatedPartiesDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsSalestoRelatedPartiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_f94544f4-2523-47d7-a7c5-a9f13a08338e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_0785636b-6d2d-4c99-9a90-7ac78fe6b3d3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f94544f4-2523-47d7-a7c5-a9f13a08338e" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_0785636b-6d2d-4c99-9a90-7ac78fe6b3d3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_f5e81e45-67f1-4a35-b966-8cab86420550" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_0785636b-6d2d-4c99-9a90-7ac78fe6b3d3" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_f5e81e45-67f1-4a35-b966-8cab86420550" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_f5e81e45-67f1-4a35-b966-8cab86420550_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_f5e81e45-67f1-4a35-b966-8cab86420550" xlink:to="loc_us-gaap_RelatedPartyDomain_f5e81e45-67f1-4a35-b966-8cab86420550_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_7ddcf4f4-b9ee-40ae-b443-38dead593f11" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_f5e81e45-67f1-4a35-b966-8cab86420550" xlink:to="loc_us-gaap_RelatedPartyDomain_7ddcf4f4-b9ee-40ae-b443-38dead593f11" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_37e9cc55-c680-4f78-83d2-7ef8901e8db8" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_7ddcf4f4-b9ee-40ae-b443-38dead593f11" xlink:to="loc_srt_AffiliatedEntityMember_37e9cc55-c680-4f78-83d2-7ef8901e8db8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_8269b4b9-0827-413c-85b6-09f124bb0d0b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f94544f4-2523-47d7-a7c5-a9f13a08338e" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_8269b4b9-0827-413c-85b6-09f124bb0d0b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ReductionToNetSalesWestlakeFromChargesForNonVariableCostsOfProduction_a1d1e648-d535-4ae3-8930-7a53bc449bb8" xlink:href="wlkp-20240930.xsd#wlkp_ReductionToNetSalesWestlakeFromChargesForNonVariableCostsOfProduction"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f94544f4-2523-47d7-a7c5-a9f13a08338e" xlink:to="loc_wlkp_ReductionToNetSalesWestlakeFromChargesForNonVariableCostsOfProduction_a1d1e648-d535-4ae3-8930-7a53bc449bb8" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsCostofSalesfromRelatedPartiesDetails" xlink:type="simple" xlink:href="wlkp-20240930.xsd#RelatedPartyTransactionsCostofSalesfromRelatedPartiesDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsCostofSalesfromRelatedPartiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_6aced413-400f-4105-a08d-cf5b5337c7df" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_607e220c-7148-4946-a5fe-1149d1ac7af1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_6aced413-400f-4105-a08d-cf5b5337c7df" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_607e220c-7148-4946-a5fe-1149d1ac7af1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_c6432692-69dd-4748-81ab-846b3bf8583f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_607e220c-7148-4946-a5fe-1149d1ac7af1" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_c6432692-69dd-4748-81ab-846b3bf8583f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_c6432692-69dd-4748-81ab-846b3bf8583f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_c6432692-69dd-4748-81ab-846b3bf8583f" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_c6432692-69dd-4748-81ab-846b3bf8583f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_aefe111e-aeb3-4c9f-a12b-e34eeca4955b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_c6432692-69dd-4748-81ab-846b3bf8583f" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_aefe111e-aeb3-4c9f-a12b-e34eeca4955b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_FeedstockPurchasedMember_88ed716f-74b6-4d0a-8315-4f986e5ad416" xlink:href="wlkp-20240930.xsd#wlkp_FeedstockPurchasedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_aefe111e-aeb3-4c9f-a12b-e34eeca4955b" xlink:to="loc_wlkp_FeedstockPurchasedMember_88ed716f-74b6-4d0a-8315-4f986e5ad416" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_OtherServiceChargesMember_45bafe7f-3367-4665-aa42-ef750cf7f24b" xlink:href="wlkp-20240930.xsd#wlkp_OtherServiceChargesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_aefe111e-aeb3-4c9f-a12b-e34eeca4955b" xlink:to="loc_wlkp_OtherServiceChargesMember_45bafe7f-3367-4665-aa42-ef750cf7f24b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1e917663-74e4-43b2-aca7-49c069acd832" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_607e220c-7148-4946-a5fe-1149d1ac7af1" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1e917663-74e4-43b2-aca7-49c069acd832" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_1e917663-74e4-43b2-aca7-49c069acd832_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1e917663-74e4-43b2-aca7-49c069acd832" xlink:to="loc_us-gaap_RelatedPartyDomain_1e917663-74e4-43b2-aca7-49c069acd832_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_333821e1-dba5-4a34-b972-69779c443a8f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1e917663-74e4-43b2-aca7-49c069acd832" xlink:to="loc_us-gaap_RelatedPartyDomain_333821e1-dba5-4a34-b972-69779c443a8f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_48af4d5d-2870-44a1-9c19-f353e2a6c330" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_333821e1-dba5-4a34-b972-69779c443a8f" xlink:to="loc_srt_AffiliatedEntityMember_48af4d5d-2870-44a1-9c19-f353e2a6c330" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_9a3492cb-1c3a-487a-b87d-83fb7ff5138d" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_607e220c-7148-4946-a5fe-1149d1ac7af1" xlink:to="loc_srt_CounterpartyNameAxis_9a3492cb-1c3a-487a-b87d-83fb7ff5138d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_9a3492cb-1c3a-487a-b87d-83fb7ff5138d_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_9a3492cb-1c3a-487a-b87d-83fb7ff5138d" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_9a3492cb-1c3a-487a-b87d-83fb7ff5138d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_43fd9f80-f498-403e-9941-c9c0093bfa51" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_9a3492cb-1c3a-487a-b87d-83fb7ff5138d" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_43fd9f80-f498-403e-9941-c9c0093bfa51" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_2bc32c58-8f0b-445a-b7b9-13c4591a421a" xlink:href="wlkp-20240930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_43fd9f80-f498-403e-9941-c9c0093bfa51" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_2bc32c58-8f0b-445a-b7b9-13c4591a421a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartiesAmountInCostOfSales_4582106c-c8ca-41d7-be4a-51c6f0e79631" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartiesAmountInCostOfSales"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_6aced413-400f-4105-a08d-cf5b5337c7df" xlink:to="loc_us-gaap_RelatedPartiesAmountInCostOfSales_4582106c-c8ca-41d7-be4a-51c6f0e79631" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsServicesfromRelatedPartiesIncludedinSGAExpensesDetails" xlink:type="simple" xlink:href="wlkp-20240930.xsd#RelatedPartyTransactionsServicesfromRelatedPartiesIncludedinSGAExpensesDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsServicesfromRelatedPartiesIncludedinSGAExpensesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_c6dab7d7-6c4e-415d-a5f8-842115103df1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_8f63ae6d-682a-437b-a6e5-d9b3c5b9e98b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_c6dab7d7-6c4e-415d-a5f8-842115103df1" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_8f63ae6d-682a-437b-a6e5-d9b3c5b9e98b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_3c97350e-2bf1-4f2a-b21d-d570cba8c887" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_8f63ae6d-682a-437b-a6e5-d9b3c5b9e98b" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_3c97350e-2bf1-4f2a-b21d-d570cba8c887" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_3c97350e-2bf1-4f2a-b21d-d570cba8c887_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_3c97350e-2bf1-4f2a-b21d-d570cba8c887" xlink:to="loc_us-gaap_RelatedPartyDomain_3c97350e-2bf1-4f2a-b21d-d570cba8c887_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_e3025cfe-9381-408b-9cda-61a5bb95e996" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_3c97350e-2bf1-4f2a-b21d-d570cba8c887" xlink:to="loc_us-gaap_RelatedPartyDomain_e3025cfe-9381-408b-9cda-61a5bb95e996" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_74e2223f-fc48-4dd9-afe4-7eff8ffebacd" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_e3025cfe-9381-408b-9cda-61a5bb95e996" xlink:to="loc_srt_AffiliatedEntityMember_74e2223f-fc48-4dd9-afe4-7eff8ffebacd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_5fc0f7b8-6bd3-44eb-ae1d-a42818499512" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_8f63ae6d-682a-437b-a6e5-d9b3c5b9e98b" xlink:to="loc_srt_CounterpartyNameAxis_5fc0f7b8-6bd3-44eb-ae1d-a42818499512" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_5fc0f7b8-6bd3-44eb-ae1d-a42818499512_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_5fc0f7b8-6bd3-44eb-ae1d-a42818499512" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_5fc0f7b8-6bd3-44eb-ae1d-a42818499512_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_7ba9e2db-e17f-4c58-a799-c5b511ea1f55" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_5fc0f7b8-6bd3-44eb-ae1d-a42818499512" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_7ba9e2db-e17f-4c58-a799-c5b511ea1f55" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_213ddd91-dfee-47df-bb20-9a5bf96fb419" xlink:href="wlkp-20240930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_7ba9e2db-e17f-4c58-a799-c5b511ea1f55" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_213ddd91-dfee-47df-bb20-9a5bf96fb419" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_ba7b0b4f-b53f-4127-9230-64212c701fda" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_c6dab7d7-6c4e-415d-a5f8-842115103df1" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_ba7b0b4f-b53f-4127-9230-64212c701fda" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsGoodsandServicesPurchasedfromWestlakeandCapitalizedasAssetsDetails" xlink:type="simple" xlink:href="wlkp-20240930.xsd#RelatedPartyTransactionsGoodsandServicesPurchasedfromWestlakeandCapitalizedasAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsGoodsandServicesPurchasedfromWestlakeandCapitalizedasAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_1b3ce06b-22e7-4cd5-991d-72549eebec34" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_a4a3c3d3-6d9d-4640-9336-7458955f053c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_1b3ce06b-22e7-4cd5-991d-72549eebec34" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_a4a3c3d3-6d9d-4640-9336-7458955f053c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_9b213c4e-a41f-4474-9c45-4615a2560c9e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_a4a3c3d3-6d9d-4640-9336-7458955f053c" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_9b213c4e-a41f-4474-9c45-4615a2560c9e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_9b213c4e-a41f-4474-9c45-4615a2560c9e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_9b213c4e-a41f-4474-9c45-4615a2560c9e" xlink:to="loc_us-gaap_RelatedPartyDomain_9b213c4e-a41f-4474-9c45-4615a2560c9e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_7647c6e1-98e3-4c52-b0d1-59b00c7dde21" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_9b213c4e-a41f-4474-9c45-4615a2560c9e" xlink:to="loc_us-gaap_RelatedPartyDomain_7647c6e1-98e3-4c52-b0d1-59b00c7dde21" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_4a4412b2-4d6b-422e-9e6a-63f3d21a3e62" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_7647c6e1-98e3-4c52-b0d1-59b00c7dde21" xlink:to="loc_srt_AffiliatedEntityMember_4a4412b2-4d6b-422e-9e6a-63f3d21a3e62" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_53251086-608c-41b3-a00c-82c4e18c78f5" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_a4a3c3d3-6d9d-4640-9336-7458955f053c" xlink:to="loc_srt_CounterpartyNameAxis_53251086-608c-41b3-a00c-82c4e18c78f5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_53251086-608c-41b3-a00c-82c4e18c78f5_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_53251086-608c-41b3-a00c-82c4e18c78f5" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_53251086-608c-41b3-a00c-82c4e18c78f5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_7b92e2ad-340e-4dfe-b33b-21107ccf6562" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_53251086-608c-41b3-a00c-82c4e18c78f5" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_7b92e2ad-340e-4dfe-b33b-21107ccf6562" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_3776f7af-24a6-46ed-9076-026f22630d00" xlink:href="wlkp-20240930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_7b92e2ad-340e-4dfe-b33b-21107ccf6562" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_3776f7af-24a6-46ed-9076-026f22630d00" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_RelatedPartyTransactionPurchasesFromRelatedPartyCapitalizedAsAssets_a47b03aa-1773-43d3-8ebb-845415f77946" xlink:href="wlkp-20240930.xsd#wlkp_RelatedPartyTransactionPurchasesFromRelatedPartyCapitalizedAsAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_1b3ce06b-22e7-4cd5-991d-72549eebec34" xlink:to="loc_wlkp_RelatedPartyTransactionPurchasesFromRelatedPartyCapitalizedAsAssets_a47b03aa-1773-43d3-8ebb-845415f77946" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsAccountsReceivablefromandAccountsPayabletoRelatedPartiesDetails" xlink:type="simple" xlink:href="wlkp-20240930.xsd#RelatedPartyTransactionsAccountsReceivablefromandAccountsPayabletoRelatedPartiesDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsAccountsReceivablefromandAccountsPayabletoRelatedPartiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_b9becadf-1a6a-457a-9480-6c263097ed65" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_a275451c-e088-47c0-a0f9-d39f927cf78c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_b9becadf-1a6a-457a-9480-6c263097ed65" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_a275451c-e088-47c0-a0f9-d39f927cf78c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_18f86561-0877-4751-905b-0785964e87b5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_a275451c-e088-47c0-a0f9-d39f927cf78c" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_18f86561-0877-4751-905b-0785964e87b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_18f86561-0877-4751-905b-0785964e87b5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_18f86561-0877-4751-905b-0785964e87b5" xlink:to="loc_us-gaap_RelatedPartyDomain_18f86561-0877-4751-905b-0785964e87b5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_6cc46a48-4bdc-4096-9c52-dd3b302ef3f1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_18f86561-0877-4751-905b-0785964e87b5" xlink:to="loc_us-gaap_RelatedPartyDomain_6cc46a48-4bdc-4096-9c52-dd3b302ef3f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_fa508aee-0e5b-401d-a6a7-24098944b223" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_6cc46a48-4bdc-4096-9c52-dd3b302ef3f1" xlink:to="loc_srt_AffiliatedEntityMember_fa508aee-0e5b-401d-a6a7-24098944b223" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_ba3de441-7685-4010-baab-a9103c3b45af" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_a275451c-e088-47c0-a0f9-d39f927cf78c" xlink:to="loc_srt_CounterpartyNameAxis_ba3de441-7685-4010-baab-a9103c3b45af" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_ba3de441-7685-4010-baab-a9103c3b45af_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_ba3de441-7685-4010-baab-a9103c3b45af" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_ba3de441-7685-4010-baab-a9103c3b45af_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_82cbf925-db61-48a7-b336-338eb4d3c5f1" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_ba3de441-7685-4010-baab-a9103c3b45af" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_82cbf925-db61-48a7-b336-338eb4d3c5f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_d2265d52-be61-4696-bdb9-ae6c57c0ea7c" xlink:href="wlkp-20240930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_82cbf925-db61-48a7-b336-338eb4d3c5f1" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_d2265d52-be61-4696-bdb9-ae6c57c0ea7c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_2c8d6720-23ad-4c5c-b7ad-72c023dc6d1e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_a275451c-e088-47c0-a0f9-d39f927cf78c" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_2c8d6720-23ad-4c5c-b7ad-72c023dc6d1e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_2c8d6720-23ad-4c5c-b7ad-72c023dc6d1e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_2c8d6720-23ad-4c5c-b7ad-72c023dc6d1e" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_2c8d6720-23ad-4c5c-b7ad-72c023dc6d1e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_057e8a54-0960-4cb3-bde7-c8d0d42c113c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_2c8d6720-23ad-4c5c-b7ad-72c023dc6d1e" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_057e8a54-0960-4cb3-bde7-c8d0d42c113c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableMember_fd3baa74-d81b-49b7-9bb3-5614b6149626" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccountsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_057e8a54-0960-4cb3-bde7-c8d0d42c113c" xlink:to="loc_us-gaap_AccountsReceivableMember_fd3baa74-d81b-49b7-9bb3-5614b6149626" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_IMAPartnershipEarnedAmountAddedToMarketRateBasisPoints_072c86b8-da72-490e-aca6-5f03d7f0b35b" xlink:href="wlkp-20240930.xsd#wlkp_IMAPartnershipEarnedAmountAddedToMarketRateBasisPoints"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_b9becadf-1a6a-457a-9480-6c263097ed65" xlink:to="loc_wlkp_IMAPartnershipEarnedAmountAddedToMarketRateBasisPoints_072c86b8-da72-490e-aca6-5f03d7f0b35b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_AccruedinterestincludedinreceivableunderIMA_3e266ec8-c8e4-41c9-bb72-1d9ce3f6874b" xlink:href="wlkp-20240930.xsd#wlkp_AccruedinterestincludedinreceivableunderIMA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_b9becadf-1a6a-457a-9480-6c263097ed65" xlink:to="loc_wlkp_AccruedinterestincludedinreceivableunderIMA_3e266ec8-c8e4-41c9-bb72-1d9ce3f6874b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_InterestearnedrelatedtotheIMA_2f2ad188-9b0b-4b8e-b5f9-c2a936587c08" xlink:href="wlkp-20240930.xsd#wlkp_InterestearnedrelatedtotheIMA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_b9becadf-1a6a-457a-9480-6c263097ed65" xlink:to="loc_wlkp_InterestearnedrelatedtotheIMA_2f2ad188-9b0b-4b8e-b5f9-c2a936587c08" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ReceivablesunderInvestmentManagementAgreementswithRelatedPartiesCurrent_bf5478ac-cf14-4c7f-bce2-2ba20462b754" xlink:href="wlkp-20240930.xsd#wlkp_ReceivablesunderInvestmentManagementAgreementswithRelatedPartiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_b9becadf-1a6a-457a-9480-6c263097ed65" xlink:to="loc_wlkp_ReceivablesunderInvestmentManagementAgreementswithRelatedPartiesCurrent_bf5478ac-cf14-4c7f-bce2-2ba20462b754" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ShortfallFees_83cf9f6d-5495-4976-9c4a-a04ee891944c" xlink:href="wlkp-20240930.xsd#wlkp_ShortfallFees"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_b9becadf-1a6a-457a-9480-6c263097ed65" xlink:to="loc_wlkp_ShortfallFees_83cf9f6d-5495-4976-9c4a-a04ee891944c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ShortfallFeesRecovered_f72a3106-17c5-416a-b3cf-c8595d1cedad" xlink:href="wlkp-20240930.xsd#wlkp_ShortfallFeesRecovered"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_b9becadf-1a6a-457a-9480-6c263097ed65" xlink:to="loc_wlkp_ShortfallFeesRecovered_f72a3106-17c5-416a-b3cf-c8595d1cedad" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_f836ddcc-c3f9-4315-8a00-3fe9a13e9478" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_b9becadf-1a6a-457a-9480-6c263097ed65" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_f836ddcc-c3f9-4315-8a00-3fe9a13e9478" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ReductionToNetSalesWestlakeFromChargesForNonVariableCostsOfProduction_ff78ae6b-f905-40b3-80c2-4b548d7259e8" xlink:href="wlkp-20240930.xsd#wlkp_ReductionToNetSalesWestlakeFromChargesForNonVariableCostsOfProduction"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_b9becadf-1a6a-457a-9480-6c263097ed65" xlink:to="loc_wlkp_ReductionToNetSalesWestlakeFromChargesForNonVariableCostsOfProduction_ff78ae6b-f905-40b3-80c2-4b548d7259e8" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_e961ab6a-c79e-489b-9b71-3e850e9a4c47" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_b9becadf-1a6a-457a-9480-6c263097ed65" xlink:to="loc_us-gaap_AccountsPayableCurrent_e961ab6a-c79e-489b-9b71-3e850e9a4c47" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsGeneralDetails" xlink:type="simple" xlink:href="wlkp-20240930.xsd#RelatedPartyTransactionsGeneralDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsGeneralDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_a8ad26f1-8963-4a63-a263-e3b6af2a7ec7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_ea8e04ee-d8f7-4d2a-9850-b449bb26cc88" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_a8ad26f1-8963-4a63-a263-e3b6af2a7ec7" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_ea8e04ee-d8f7-4d2a-9850-b449bb26cc88" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2ca55493-4136-48ca-9722-13f9c69a0e55" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_ea8e04ee-d8f7-4d2a-9850-b449bb26cc88" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2ca55493-4136-48ca-9722-13f9c69a0e55" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_2ca55493-4136-48ca-9722-13f9c69a0e55_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2ca55493-4136-48ca-9722-13f9c69a0e55" xlink:to="loc_us-gaap_RelatedPartyDomain_2ca55493-4136-48ca-9722-13f9c69a0e55_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_7590642c-57f6-43e4-9cb8-820f35b10f15" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2ca55493-4136-48ca-9722-13f9c69a0e55" xlink:to="loc_us-gaap_RelatedPartyDomain_7590642c-57f6-43e4-9cb8-820f35b10f15" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_7b749484-61dd-47f5-a448-8d7b92ef24f4" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_7590642c-57f6-43e4-9cb8-820f35b10f15" xlink:to="loc_srt_AffiliatedEntityMember_7b749484-61dd-47f5-a448-8d7b92ef24f4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_888cd593-57eb-4235-8e28-42e5ce86ef03" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_ea8e04ee-d8f7-4d2a-9850-b449bb26cc88" xlink:to="loc_srt_CounterpartyNameAxis_888cd593-57eb-4235-8e28-42e5ce86ef03" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_888cd593-57eb-4235-8e28-42e5ce86ef03_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_888cd593-57eb-4235-8e28-42e5ce86ef03" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_888cd593-57eb-4235-8e28-42e5ce86ef03_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_450b0ef3-473c-4839-9786-2fc7700d9354" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_888cd593-57eb-4235-8e28-42e5ce86ef03" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_450b0ef3-473c-4839-9786-2fc7700d9354" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_733fa099-d26c-4e01-91d9-ba6d3ce5b72a" xlink:href="wlkp-20240930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_450b0ef3-473c-4839-9786-2fc7700d9354" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_733fa099-d26c-4e01-91d9-ba6d3ce5b72a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseExpense_183b9aa8-d346-41c7-9ade-ca8f93037ab0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingLeaseExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_a8ad26f1-8963-4a63-a263-e3b6af2a7ec7" xlink:to="loc_us-gaap_OperatingLeaseExpense_183b9aa8-d346-41c7-9ade-ca8f93037ab0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_Siteleaseagreementnumber_acb91968-c840-48d1-bd98-b453acd620a7" xlink:href="wlkp-20240930.xsd#wlkp_Siteleaseagreementnumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_a8ad26f1-8963-4a63-a263-e3b6af2a7ec7" xlink:to="loc_wlkp_Siteleaseagreementnumber_acb91968-c840-48d1-bd98-b453acd620a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_Siteleaseagreementsterminyears_321334bb-b8eb-4514-8eb2-072dccc670d7" xlink:href="wlkp-20240930.xsd#wlkp_Siteleaseagreementsterminyears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_a8ad26f1-8963-4a63-a263-e3b6af2a7ec7" xlink:to="loc_wlkp_Siteleaseagreementsterminyears_321334bb-b8eb-4514-8eb2-072dccc670d7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_SiteLeaseAgreementsAnnualProceedsPerSite_4016cbd9-c002-4f8a-8c7c-601d8fc56418" xlink:href="wlkp-20240930.xsd#wlkp_SiteLeaseAgreementsAnnualProceedsPerSite"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_a8ad26f1-8963-4a63-a263-e3b6af2a7ec7" xlink:to="loc_wlkp_SiteLeaseAgreementsAnnualProceedsPerSite_4016cbd9-c002-4f8a-8c7c-601d8fc56418" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsDebtPayabletoRelatedPartiesDetails" xlink:type="simple" xlink:href="wlkp-20240930.xsd#RelatedPartyTransactionsDebtPayabletoRelatedPartiesDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsDebtPayabletoRelatedPartiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_ee525f9b-72d9-4ab1-8d4b-145e81c4d0dd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_054b91e4-26f6-40d0-b261-37f08fbce425" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_ee525f9b-72d9-4ab1-8d4b-145e81c4d0dd" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_054b91e4-26f6-40d0-b261-37f08fbce425" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_62f55434-3cc0-4b04-8abb-e95a5870966b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_054b91e4-26f6-40d0-b261-37f08fbce425" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_62f55434-3cc0-4b04-8abb-e95a5870966b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_62f55434-3cc0-4b04-8abb-e95a5870966b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_62f55434-3cc0-4b04-8abb-e95a5870966b" xlink:to="loc_us-gaap_RelatedPartyDomain_62f55434-3cc0-4b04-8abb-e95a5870966b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_c38e63ba-1048-430d-b8fb-1b94900ad388" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_62f55434-3cc0-4b04-8abb-e95a5870966b" xlink:to="loc_us-gaap_RelatedPartyDomain_c38e63ba-1048-430d-b8fb-1b94900ad388" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_833887d8-c087-4dac-a296-7213953607d3" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_c38e63ba-1048-430d-b8fb-1b94900ad388" xlink:to="loc_srt_AffiliatedEntityMember_833887d8-c087-4dac-a296-7213953607d3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_3a7a3e43-9ac1-447b-b21d-c536acb33768" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_054b91e4-26f6-40d0-b261-37f08fbce425" xlink:to="loc_srt_CounterpartyNameAxis_3a7a3e43-9ac1-447b-b21d-c536acb33768" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_3a7a3e43-9ac1-447b-b21d-c536acb33768_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_3a7a3e43-9ac1-447b-b21d-c536acb33768" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_3a7a3e43-9ac1-447b-b21d-c536acb33768_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_b18b66b0-96b5-4004-bea6-faed67c8cfaf" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_3a7a3e43-9ac1-447b-b21d-c536acb33768" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_b18b66b0-96b5-4004-bea6-faed67c8cfaf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_f65d4dbb-9c5e-4102-9cdf-b8e2355f68d8" xlink:href="wlkp-20240930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_b18b66b0-96b5-4004-bea6-faed67c8cfaf" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_f65d4dbb-9c5e-4102-9cdf-b8e2355f68d8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_d4a9572a-129a-46e1-8737-1d4b51de1a51" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_054b91e4-26f6-40d0-b261-37f08fbce425" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_d4a9572a-129a-46e1-8737-1d4b51de1a51" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_d4a9572a-129a-46e1-8737-1d4b51de1a51_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_d4a9572a-129a-46e1-8737-1d4b51de1a51" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_d4a9572a-129a-46e1-8737-1d4b51de1a51_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_7d7ee49a-d083-449d-8673-af47d19f1c85" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_d4a9572a-129a-46e1-8737-1d4b51de1a51" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_7d7ee49a-d083-449d-8673-af47d19f1c85" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpenseMember_f8a81857-40ca-400e-b4b4-c093b258f1f1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherNonoperatingIncomeExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_7d7ee49a-d083-449d-8673-af47d19f1c85" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpenseMember_f8a81857-40ca-400e-b4b4-c093b258f1f1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_fd5dd370-a574-4637-80d4-153bef70913a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_054b91e4-26f6-40d0-b261-37f08fbce425" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_fd5dd370-a574-4637-80d4-153bef70913a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_fd5dd370-a574-4637-80d4-153bef70913a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_fd5dd370-a574-4637-80d4-153bef70913a" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_fd5dd370-a574-4637-80d4-153bef70913a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_8297819e-d6ef-4e52-891a-7259b7a1f4da" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_fd5dd370-a574-4637-80d4-153bef70913a" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_8297819e-d6ef-4e52-891a-7259b7a1f4da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesMember_4b90168f-9289-487f-89a5-bf8c1d753db6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccruedLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_8297819e-d6ef-4e52-891a-7259b7a1f4da" xlink:to="loc_us-gaap_AccruedLiabilitiesMember_4b90168f-9289-487f-89a5-bf8c1d753db6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense_3ccfcca1-6f71-4501-a739-6e7455ec6c01" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_ee525f9b-72d9-4ab1-8d4b-145e81c4d0dd" xlink:to="loc_us-gaap_InterestExpense_3ccfcca1-6f71-4501-a739-6e7455ec6c01" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPayableCurrent_dc373adc-77d8-40b4-8099-17a16f030860" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_ee525f9b-72d9-4ab1-8d4b-145e81c4d0dd" xlink:to="loc_us-gaap_InterestPayableCurrent_dc373adc-77d8-40b4-8099-17a16f030860" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLongTermDebtNoncurrent_c147b0f8-9b66-4d23-a28f-43018da4fde1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherLongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_ee525f9b-72d9-4ab1-8d4b-145e81c4d0dd" xlink:to="loc_us-gaap_OtherLongTermDebtNoncurrent_c147b0f8-9b66-4d23-a28f-43018da4fde1" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsMajorCustomerandConcentrationRiskDetails" xlink:type="simple" xlink:href="wlkp-20240930.xsd#RelatedPartyTransactionsMajorCustomerandConcentrationRiskDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsMajorCustomerandConcentrationRiskDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_22662ab1-6fb8-4eaa-8f7e-291af568a34d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTable_b9b4c883-f7c8-4be4-9eaf-14d2da86fcd2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_22662ab1-6fb8-4eaa-8f7e-291af568a34d" xlink:to="loc_us-gaap_ConcentrationRiskTable_b9b4c883-f7c8-4be4-9eaf-14d2da86fcd2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_d292afc7-7ca2-4ef3-8f6a-6afb41b8ec42" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_b9b4c883-f7c8-4be4-9eaf-14d2da86fcd2" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_d292afc7-7ca2-4ef3-8f6a-6afb41b8ec42" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_d292afc7-7ca2-4ef3-8f6a-6afb41b8ec42_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_d292afc7-7ca2-4ef3-8f6a-6afb41b8ec42" xlink:to="loc_us-gaap_RelatedPartyDomain_d292afc7-7ca2-4ef3-8f6a-6afb41b8ec42_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_9380e90a-f09a-4e87-8155-be27bf2b6483" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_d292afc7-7ca2-4ef3-8f6a-6afb41b8ec42" xlink:to="loc_us-gaap_RelatedPartyDomain_9380e90a-f09a-4e87-8155-be27bf2b6483" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_a0bc08d2-df12-4497-a7de-5e150aa98f76" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_9380e90a-f09a-4e87-8155-be27bf2b6483" xlink:to="loc_srt_AffiliatedEntityMember_a0bc08d2-df12-4497-a7de-5e150aa98f76" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_c68e3eea-e3f6-4894-b43c-282ea2987a31" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_b9b4c883-f7c8-4be4-9eaf-14d2da86fcd2" xlink:to="loc_srt_MajorCustomersAxis_c68e3eea-e3f6-4894-b43c-282ea2987a31" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_c68e3eea-e3f6-4894-b43c-282ea2987a31_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_c68e3eea-e3f6-4894-b43c-282ea2987a31" xlink:to="loc_srt_NameOfMajorCustomerDomain_c68e3eea-e3f6-4894-b43c-282ea2987a31_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_739bf116-6438-4cc4-8b99-ccbbd09b5b97" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_c68e3eea-e3f6-4894-b43c-282ea2987a31" xlink:to="loc_srt_NameOfMajorCustomerDomain_739bf116-6438-4cc4-8b99-ccbbd09b5b97" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_3d6217fd-a285-4659-8117-f1a9a5f0e626" xlink:href="wlkp-20240930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_739bf116-6438-4cc4-8b99-ccbbd09b5b97" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_3d6217fd-a285-4659-8117-f1a9a5f0e626" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_6cb802a8-e58a-4ec3-9a2e-520252ef3889" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_b9b4c883-f7c8-4be4-9eaf-14d2da86fcd2" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_6cb802a8-e58a-4ec3-9a2e-520252ef3889" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_6cb802a8-e58a-4ec3-9a2e-520252ef3889_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_6cb802a8-e58a-4ec3-9a2e-520252ef3889" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_6cb802a8-e58a-4ec3-9a2e-520252ef3889_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_ea946c0d-deac-42b7-9130-c2c0296a13c9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_6cb802a8-e58a-4ec3-9a2e-520252ef3889" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_ea946c0d-deac-42b7-9130-c2c0296a13c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesRevenueNetMember_becae573-ad93-4546-9ea1-30c8eab54c55" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SalesRevenueNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_ea946c0d-deac-42b7-9130-c2c0296a13c9" xlink:to="loc_us-gaap_SalesRevenueNetMember_becae573-ad93-4546-9ea1-30c8eab54c55" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_4d2e6b28-ccb0-4b6f-a7a9-d1e78f37f7dd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_b9b4c883-f7c8-4be4-9eaf-14d2da86fcd2" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_4d2e6b28-ccb0-4b6f-a7a9-d1e78f37f7dd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_4d2e6b28-ccb0-4b6f-a7a9-d1e78f37f7dd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_4d2e6b28-ccb0-4b6f-a7a9-d1e78f37f7dd" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_4d2e6b28-ccb0-4b6f-a7a9-d1e78f37f7dd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_4dc61a71-8ae6-49ad-9106-82a0feebd6c9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_4d2e6b28-ccb0-4b6f-a7a9-d1e78f37f7dd" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_4dc61a71-8ae6-49ad-9106-82a0feebd6c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_56eb2ba9-86f1-4d1c-aaf9-cc3a99532252" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_4dc61a71-8ae6-49ad-9106-82a0feebd6c9" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_56eb2ba9-86f1-4d1c-aaf9-cc3a99532252" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_d7906caf-f5a6-44e1-a686-37c452b571c8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_22662ab1-6fb8-4eaa-8f7e-291af568a34d" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_d7906caf-f5a6-44e1-a686-37c452b571c8" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/LongTermDebtPayabletoWestlakeDetails" xlink:type="simple" xlink:href="wlkp-20240930.xsd#LongTermDebtPayabletoWestlakeDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/LongTermDebtPayabletoWestlakeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_66c9c01d-a4c3-48c4-83aa-749670bc591e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_dfb62502-0607-4a21-af2e-5ff87eb259de" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_66c9c01d-a4c3-48c4-83aa-749670bc591e" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_dfb62502-0607-4a21-af2e-5ff87eb259de" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_ea067ea4-4976-4cc3-a156-aff015f5e8bb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_dfb62502-0607-4a21-af2e-5ff87eb259de" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_ea067ea4-4976-4cc3-a156-aff015f5e8bb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_ea067ea4-4976-4cc3-a156-aff015f5e8bb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_ea067ea4-4976-4cc3-a156-aff015f5e8bb" xlink:to="loc_us-gaap_RelatedPartyDomain_ea067ea4-4976-4cc3-a156-aff015f5e8bb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_36381cbf-a372-41b6-84a9-45ed50426d7e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_ea067ea4-4976-4cc3-a156-aff015f5e8bb" xlink:to="loc_us-gaap_RelatedPartyDomain_36381cbf-a372-41b6-84a9-45ed50426d7e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnerMember_ea3d567f-f607-46ef-9a3e-23137d926073" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedPartnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_36381cbf-a372-41b6-84a9-45ed50426d7e" xlink:to="loc_us-gaap_LimitedPartnerMember_ea3d567f-f607-46ef-9a3e-23137d926073" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_795a33fa-e324-47af-85cc-2dfa03c50b15" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_dfb62502-0607-4a21-af2e-5ff87eb259de" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_795a33fa-e324-47af-85cc-2dfa03c50b15" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_795a33fa-e324-47af-85cc-2dfa03c50b15_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_795a33fa-e324-47af-85cc-2dfa03c50b15" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_795a33fa-e324-47af-85cc-2dfa03c50b15_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_557cd46f-bf68-4bc1-92fb-d552e7140d88" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_795a33fa-e324-47af-85cc-2dfa03c50b15" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_557cd46f-bf68-4bc1-92fb-d552e7140d88" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_SeniorUnsecuredRevolvingCreditFacilityMember_5fbadcbc-f278-44d8-8549-020884f17377" xlink:href="wlkp-20240930.xsd#wlkp_SeniorUnsecuredRevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_557cd46f-bf68-4bc1-92fb-d552e7140d88" xlink:to="loc_wlkp_SeniorUnsecuredRevolvingCreditFacilityMember_5fbadcbc-f278-44d8-8549-020884f17377" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_d473dbf7-001f-4df1-881f-6eb9de67946e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_dfb62502-0607-4a21-af2e-5ff87eb259de" xlink:to="loc_us-gaap_DebtInstrumentAxis_d473dbf7-001f-4df1-881f-6eb9de67946e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_d473dbf7-001f-4df1-881f-6eb9de67946e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_d473dbf7-001f-4df1-881f-6eb9de67946e" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_d473dbf7-001f-4df1-881f-6eb9de67946e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_4ae769b8-9ec4-4062-ad31-699ab229f60e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_d473dbf7-001f-4df1-881f-6eb9de67946e" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_4ae769b8-9ec4-4062-ad31-699ab229f60e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_OpCoRevolverMember_496ae520-2c3a-420b-ae25-50b65babac01" xlink:href="wlkp-20240930.xsd#wlkp_OpCoRevolverMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_4ae769b8-9ec4-4062-ad31-699ab229f60e" xlink:to="loc_wlkp_OpCoRevolverMember_496ae520-2c3a-420b-ae25-50b65babac01" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_MLPRevolverMember_6d22083f-3ff3-4d15-b2ff-e7cf68c400d2" xlink:href="wlkp-20240930.xsd#wlkp_MLPRevolverMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_4ae769b8-9ec4-4062-ad31-699ab229f60e" xlink:to="loc_wlkp_MLPRevolverMember_6d22083f-3ff3-4d15-b2ff-e7cf68c400d2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_c31c2fbe-19b5-4315-98e8-7974af3ba84a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_dfb62502-0607-4a21-af2e-5ff87eb259de" xlink:to="loc_us-gaap_VariableRateAxis_c31c2fbe-19b5-4315-98e8-7974af3ba84a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_c31c2fbe-19b5-4315-98e8-7974af3ba84a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_c31c2fbe-19b5-4315-98e8-7974af3ba84a" xlink:to="loc_us-gaap_VariableRateDomain_c31c2fbe-19b5-4315-98e8-7974af3ba84a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_a11324f4-59be-4867-8368-a227f28e65ac" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_c31c2fbe-19b5-4315-98e8-7974af3ba84a" xlink:to="loc_us-gaap_VariableRateDomain_a11324f4-59be-4867-8368-a227f28e65ac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_e6f40624-c197-4241-9437-c4d4fdba236a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SecuredOvernightFinancingRateSofrMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_a11324f4-59be-4867-8368-a227f28e65ac" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_e6f40624-c197-4241-9437-c4d4fdba236a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_d0e11234-780f-4f58-b668-74cd5d6ee3ee" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_dfb62502-0607-4a21-af2e-5ff87eb259de" xlink:to="loc_srt_RangeAxis_d0e11234-780f-4f58-b668-74cd5d6ee3ee" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_d0e11234-780f-4f58-b668-74cd5d6ee3ee_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_d0e11234-780f-4f58-b668-74cd5d6ee3ee" xlink:to="loc_srt_RangeMember_d0e11234-780f-4f58-b668-74cd5d6ee3ee_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_9b4ee23d-9d62-4dce-ae61-62b6ec9e226a" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_d0e11234-780f-4f58-b668-74cd5d6ee3ee" xlink:to="loc_srt_RangeMember_9b4ee23d-9d62-4dce-ae61-62b6ec9e226a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_f28b4fd1-e195-4786-bce5-4ef10a5cbd64" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_9b4ee23d-9d62-4dce-ae61-62b6ec9e226a" xlink:to="loc_srt_MinimumMember_f28b4fd1-e195-4786-bce5-4ef10a5cbd64" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_6d16438f-dfc0-4e93-ae14-fb0adc09d9c1" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_9b4ee23d-9d62-4dce-ae61-62b6ec9e226a" xlink:to="loc_srt_MaximumMember_6d16438f-dfc0-4e93-ae14-fb0adc09d9c1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLongTermDebtNoncurrent_5f805edb-6bd8-42d7-b0c6-a270ee1eef51" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherLongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_66c9c01d-a4c3-48c4-83aa-749670bc591e" xlink:to="loc_us-gaap_OtherLongTermDebtNoncurrent_5f805edb-6bd8-42d7-b0c6-a270ee1eef51" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_4be37431-2d1d-4a62-bbe1-c15aeca49157" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_66c9c01d-a4c3-48c4-83aa-749670bc591e" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_4be37431-2d1d-4a62-bbe1-c15aeca49157" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtWeightedAverageInterestRate_3be7adb2-bb29-4bcc-a725-546e0be07558" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtWeightedAverageInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_66c9c01d-a4c3-48c4-83aa-749670bc591e" xlink:to="loc_us-gaap_LongtermDebtWeightedAverageInterestRate_3be7adb2-bb29-4bcc-a725-546e0be07558" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/FairValueMeasurementsSummaryofCarryingandFairValuesofLongTermDebtDetails" xlink:type="simple" xlink:href="wlkp-20240930.xsd#FairValueMeasurementsSummaryofCarryingandFairValuesofLongTermDebtDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/FairValueMeasurementsSummaryofCarryingandFairValuesofLongTermDebtDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_7989da77-727c-471b-91e3-8accce309238" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_48a713ef-4daf-4059-b00b-f2e0ab5c9bff" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_7989da77-727c-471b-91e3-8accce309238" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_48a713ef-4daf-4059-b00b-f2e0ab5c9bff" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_e80119c2-2229-4a12-90bf-0c0d0251cbe0" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_48a713ef-4daf-4059-b00b-f2e0ab5c9bff" xlink:to="loc_srt_CounterpartyNameAxis_e80119c2-2229-4a12-90bf-0c0d0251cbe0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_e80119c2-2229-4a12-90bf-0c0d0251cbe0_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_e80119c2-2229-4a12-90bf-0c0d0251cbe0" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_e80119c2-2229-4a12-90bf-0c0d0251cbe0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_9ca7e9b2-220b-4586-ac23-3a322ded9439" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_e80119c2-2229-4a12-90bf-0c0d0251cbe0" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_9ca7e9b2-220b-4586-ac23-3a322ded9439" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_6129317b-0cd0-4871-9e3d-740ec81ded17" xlink:href="wlkp-20240930.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_9ca7e9b2-220b-4586-ac23-3a322ded9439" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_6129317b-0cd0-4871-9e3d-740ec81ded17" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1a714e4b-140a-4b76-bec6-18b7c2fb5c94" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_48a713ef-4daf-4059-b00b-f2e0ab5c9bff" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1a714e4b-140a-4b76-bec6-18b7c2fb5c94" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_1a714e4b-140a-4b76-bec6-18b7c2fb5c94_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1a714e4b-140a-4b76-bec6-18b7c2fb5c94" xlink:to="loc_us-gaap_RelatedPartyDomain_1a714e4b-140a-4b76-bec6-18b7c2fb5c94_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_6c7991a5-d6f5-4abd-8e90-be841da3f6d3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1a714e4b-140a-4b76-bec6-18b7c2fb5c94" xlink:to="loc_us-gaap_RelatedPartyDomain_6c7991a5-d6f5-4abd-8e90-be841da3f6d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_23d1c2e0-81b8-4116-930a-824befbd0a1c" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_6c7991a5-d6f5-4abd-8e90-be841da3f6d3" xlink:to="loc_srt_AffiliatedEntityMember_23d1c2e0-81b8-4116-930a-824befbd0a1c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLongTermDebtNoncurrent_ffe32368-ad8d-4560-9864-5d4688b6248e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherLongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_7989da77-727c-471b-91e3-8accce309238" xlink:to="loc_us-gaap_OtherLongTermDebtNoncurrent_ffe32368-ad8d-4560-9864-5d4688b6248e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtFairValue_6d877118-8667-4832-b1d9-0d04591a4f86" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongTermDebtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_7989da77-727c-471b-91e3-8accce309238" xlink:to="loc_us-gaap_LongTermDebtFairValue_6d877118-8667-4832-b1d9-0d04591a4f86" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/SupplementalInformationDetails" xlink:type="simple" xlink:href="wlkp-20240930.xsd#SupplementalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/SupplementalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_9994e027-4e6b-40bf-928b-ae56ee2dc734" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_9fe97751-2574-4046-a47e-f83c6c3abfc0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_9994e027-4e6b-40bf-928b-ae56ee2dc734" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_9fe97751-2574-4046-a47e-f83c6c3abfc0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_b55804a2-ede0-4c42-9d69-9f9778d89e6d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_9fe97751-2574-4046-a47e-f83c6c3abfc0" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_b55804a2-ede0-4c42-9d69-9f9778d89e6d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_b55804a2-ede0-4c42-9d69-9f9778d89e6d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_b55804a2-ede0-4c42-9d69-9f9778d89e6d" xlink:to="loc_us-gaap_RelatedPartyDomain_b55804a2-ede0-4c42-9d69-9f9778d89e6d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_af096819-4ff1-488f-8a76-3debc70ce5e0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_b55804a2-ede0-4c42-9d69-9f9778d89e6d" xlink:to="loc_us-gaap_RelatedPartyDomain_af096819-4ff1-488f-8a76-3debc70ce5e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_1bfbc844-ece3-4775-ab63-326fb66b06ba" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_af096819-4ff1-488f-8a76-3debc70ce5e0" xlink:to="loc_srt_AffiliatedEntityMember_1bfbc844-ece3-4775-ab63-326fb66b06ba" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrentAndNoncurrentAbstract_fe747bd8-6bac-4bb6-9781-548ae2d27f7f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccruedLiabilitiesCurrentAndNoncurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_9994e027-4e6b-40bf-928b-ae56ee2dc734" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrentAndNoncurrentAbstract_fe747bd8-6bac-4bb6-9781-548ae2d27f7f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_38136df1-032d-4451-aa3a-6ab50fecad4d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccruedLiabilitiesCurrentAndNoncurrentAbstract_fe747bd8-6bac-4bb6-9781-548ae2d27f7f" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_38136df1-032d-4451-aa3a-6ab50fecad4d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPayableCurrent_73179e91-776d-418b-a01b-4b33329a0ac0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccruedLiabilitiesCurrentAndNoncurrentAbstract_fe747bd8-6bac-4bb6-9781-548ae2d27f7f" xlink:to="loc_us-gaap_InterestPayableCurrent_73179e91-776d-418b-a01b-4b33329a0ac0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxesPayableCurrent_7943d2b5-a0c1-4d69-b31c-934f9b9d35db" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_TaxesPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccruedLiabilitiesCurrentAndNoncurrentAbstract_fe747bd8-6bac-4bb6-9781-548ae2d27f7f" xlink:to="loc_us-gaap_TaxesPayableCurrent_7943d2b5-a0c1-4d69-b31c-934f9b9d35db" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InsuranceRecoveries_6cebd362-4be6-42bc-97cc-87cb5be99ecf" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InsuranceRecoveries"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_9994e027-4e6b-40bf-928b-ae56ee2dc734" xlink:to="loc_us-gaap_InsuranceRecoveries_6cebd362-4be6-42bc-97cc-87cb5be99ecf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_eeb92185-a98b-44d1-8139-c98e183d9859" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CapitalExpendituresIncurredButNotYetPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_9994e027-4e6b-40bf-928b-ae56ee2dc734" xlink:to="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_eeb92185-a98b-44d1-8139-c98e183d9859" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPaidNet_6ccf7fd7-cb94-4bb3-a1d9-9a8d16c0382e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestPaidNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_9994e027-4e6b-40bf-928b-ae56ee2dc734" xlink:to="loc_us-gaap_InterestPaidNet_6ccf7fd7-cb94-4bb3-a1d9-9a8d16c0382e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_3fa92128-ab30-4e20-bfd7-fda666de4dad" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_9994e027-4e6b-40bf-928b-ae56ee2dc734" xlink:to="loc_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_3fa92128-ab30-4e20-bfd7-fda666de4dad" xlink:type="arc" order="4"/>
  </link:definitionLink>
</link:linkbase>
