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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019e78f5-a1a8-70d2-b4e8-ad81efbac93f,g:379dcb54-9a65-4535-8e7e-f1809ed048eb-->
<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://flotekind.com/role/UNAUDITEDCONDENSEDCONSOLIDATEDBALANCESHEETS" xlink:type="simple" xlink:href="ftk-20260630.xsd#UNAUDITEDCONDENSEDCONSOLIDATEDBALANCESHEETS"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/UNAUDITEDCONDENSEDCONSOLIDATEDBALANCESHEETS" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e78f5-a339-713f-94fc-94a0c585f646" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e78f5-a339-7cf3-8137-bd1afbc3a0c4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a339-713f-94fc-94a0c585f646" xlink:to="loc_us-gaap_StatementTable_019e78f5-a339-7cf3-8137-bd1afbc3a0c4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a339-73c4-9f33-db9e080fb48a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e78f5-a339-7cf3-8137-bd1afbc3a0c4" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a339-73c4-9f33-db9e080fb48a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e78f5-a339-73c4-9f33-db9e080fb48a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a339-73c4-9f33-db9e080fb48a" xlink:to="loc_us-gaap_RelatedPartyDomain_019e78f5-a339-73c4-9f33-db9e080fb48a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e78f5-a339-7d17-9e16-515bcf275459" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a339-73c4-9f33-db9e080fb48a" xlink:to="loc_us-gaap_RelatedPartyDomain_019e78f5-a339-7d17-9e16-515bcf275459" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonrelatedPartyMember_019e78f5-a339-7bda-ad26-d6bc7a2f1701" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonrelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e78f5-a339-7d17-9e16-515bcf275459" xlink:to="loc_us-gaap_NonrelatedPartyMember_019e78f5-a339-7bda-ad26-d6bc7a2f1701" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019e78f5-a339-7c2f-a8ca-4280a2545a62" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e78f5-a339-7d17-9e16-515bcf275459" xlink:to="loc_us-gaap_RelatedPartyMember_019e78f5-a339-7c2f-a8ca-4280a2545a62" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_019e78f5-a339-7319-a33c-217c49ca6b7e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a339-713f-94fc-94a0c585f646" xlink:to="loc_us-gaap_AssetsAbstract_019e78f5-a339-7319-a33c-217c49ca6b7e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrentAbstract_019e78f5-a339-7f3e-8a5d-5f910fa8eb5f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e78f5-a339-7319-a33c-217c49ca6b7e" xlink:to="loc_us-gaap_AssetsCurrentAbstract_019e78f5-a339-7f3e-8a5d-5f910fa8eb5f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019e78f5-a339-7c39-a11c-3d39ead48919" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019e78f5-a339-7f3e-8a5d-5f910fa8eb5f" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019e78f5-a339-7c39-a11c-3d39ead48919" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_019e78f5-a339-7631-9cb0-3200484562dd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019e78f5-a339-7f3e-8a5d-5f910fa8eb5f" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_019e78f5-a339-7631-9cb0-3200484562dd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_019e78f5-a339-7470-8a96-cc9c825b80c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019e78f5-a339-7f3e-8a5d-5f910fa8eb5f" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_019e78f5-a339-7470-8a96-cc9c825b80c1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_EquipmentCredit_019e78f5-a339-7e9b-b7e9-6895d39e1986" xlink:href="ftk-20260630.xsd#ftk_EquipmentCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019e78f5-a339-7f3e-8a5d-5f910fa8eb5f" xlink:to="loc_ftk_EquipmentCredit_019e78f5-a339-7e9b-b7e9-6895d39e1986" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNet_019e78f5-a339-744f-ad35-66c74957e7d6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019e78f5-a339-7f3e-8a5d-5f910fa8eb5f" xlink:to="loc_us-gaap_InventoryNet_019e78f5-a339-744f-ad35-66c74957e7d6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsCurrent_019e78f5-a339-78ec-9048-497e28a85d2a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019e78f5-a339-7f3e-8a5d-5f910fa8eb5f" xlink:to="loc_us-gaap_OtherAssetsCurrent_019e78f5-a339-78ec-9048-497e28a85d2a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetNetCurrent_019e78f5-a339-71cc-b8b1-b8e5fc216d9a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerAssetNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019e78f5-a339-7f3e-8a5d-5f910fa8eb5f" xlink:to="loc_us-gaap_ContractWithCustomerAssetNetCurrent_019e78f5-a339-71cc-b8b1-b8e5fc216d9a" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_019e78f5-a339-77bf-aeba-4da9e2ee090b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019e78f5-a339-7f3e-8a5d-5f910fa8eb5f" xlink:to="loc_us-gaap_AssetsCurrent_019e78f5-a339-77bf-aeba-4da9e2ee090b" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetNetNoncurrent_019e78f5-a339-72d0-ad00-ce006f3c39df" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerAssetNetNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e78f5-a339-7319-a33c-217c49ca6b7e" xlink:to="loc_us-gaap_ContractWithCustomerAssetNetNoncurrent_019e78f5-a339-72d0-ad00-ce006f3c39df" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_019e78f5-a339-76e5-832d-e20d880e964e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e78f5-a339-7319-a33c-217c49ca6b7e" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_019e78f5-a339-76e5-832d-e20d880e964e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_RightOfUseAsset_019e78f5-a339-7daf-aebb-b32ff3426367" xlink:href="ftk-20260630.xsd#ftk_RightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e78f5-a339-7319-a33c-217c49ca6b7e" xlink:to="loc_ftk_RightOfUseAsset_019e78f5-a339-7daf-aebb-b32ff3426367" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet_019e78f5-a339-71e1-894d-7880ff8ed37f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeTaxAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e78f5-a339-7319-a33c-217c49ca6b7e" xlink:to="loc_us-gaap_DeferredIncomeTaxAssetsNet_019e78f5-a339-71e1-894d-7880ff8ed37f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_019e78f5-a339-717b-bb8e-bc8295ef175a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e78f5-a339-7319-a33c-217c49ca6b7e" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_019e78f5-a339-717b-bb8e-bc8295ef175a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019e78f5-a339-7a03-bb1d-0956af56f651" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e78f5-a339-7319-a33c-217c49ca6b7e" xlink:to="loc_us-gaap_Assets_019e78f5-a339-7a03-bb1d-0956af56f651" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e78f5-a339-78f2-915d-a48bc1ee5a4d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a339-713f-94fc-94a0c585f646" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e78f5-a339-78f2-915d-a48bc1ee5a4d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_019e78f5-a339-7f09-8f39-a5b0144020b8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e78f5-a339-78f2-915d-a48bc1ee5a4d" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_019e78f5-a339-7f09-8f39-a5b0144020b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_019e78f5-a339-7a7e-afc7-2b535b1b43f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019e78f5-a339-7f09-8f39-a5b0144020b8" xlink:to="loc_us-gaap_AccountsPayableCurrent_019e78f5-a339-7a7e-afc7-2b535b1b43f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_019e78f5-a339-7ae5-b54b-9063ca16b3c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019e78f5-a339-7f09-8f39-a5b0144020b8" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_019e78f5-a339-7ae5-b54b-9063ca16b3c1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedIncomeTaxesCurrent_019e78f5-a339-7219-a9fb-251784127025" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedIncomeTaxesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019e78f5-a339-7f09-8f39-a5b0144020b8" xlink:to="loc_us-gaap_AccruedIncomeTaxesCurrent_019e78f5-a339-7219-a9fb-251784127025" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesCurrent_019e78f5-a339-7bc3-a12c-2c4f07c0e554" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019e78f5-a339-7f09-8f39-a5b0144020b8" xlink:to="loc_us-gaap_OtherLiabilitiesCurrent_019e78f5-a339-7bc3-a12c-2c4f07c0e554" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent_019e78f5-a339-723f-a2de-a47a87e7bd50" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019e78f5-a339-7f09-8f39-a5b0144020b8" xlink:to="loc_us-gaap_OperatingLeaseLiabilityCurrent_019e78f5-a339-723f-a2de-a47a87e7bd50" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityCurrent_019e78f5-a339-7677-9445-8ee40d1a93a1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeaseLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019e78f5-a339-7f09-8f39-a5b0144020b8" xlink:to="loc_us-gaap_FinanceLeaseLiabilityCurrent_019e78f5-a339-7677-9445-8ee40d1a93a1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LinesOfCreditCurrent_019e78f5-a339-7a75-8114-dd7a3fc33eb7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LinesOfCreditCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019e78f5-a339-7f09-8f39-a5b0144020b8" xlink:to="loc_us-gaap_LinesOfCreditCurrent_019e78f5-a339-7a75-8114-dd7a3fc33eb7" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_019e78f5-a339-75d0-8055-986529ac6ea1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019e78f5-a339-7f09-8f39-a5b0144020b8" xlink:to="loc_us-gaap_LiabilitiesCurrent_019e78f5-a339-75d0-8055-986529ac6ea1" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_019fb5f9-0afb-71b0-854e-43ad21a28d10" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e78f5-a339-78f2-915d-a48bc1ee5a4d" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_019fb5f9-0afb-71b0-854e-43ad21a28d10" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNotesPayable_019e78f5-a339-7640-bca6-853ab8061a24" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNotesPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e78f5-a339-78f2-915d-a48bc1ee5a4d" xlink:to="loc_us-gaap_OtherNotesPayable_019e78f5-a339-7640-bca6-853ab8061a24" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_019e78f5-a339-7723-97bc-0966fca6bb8a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e78f5-a339-78f2-915d-a48bc1ee5a4d" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_019e78f5-a339-7723-97bc-0966fca6bb8a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityNoncurrent_019e78f5-a339-742c-b72b-3b211924abd5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeaseLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e78f5-a339-78f2-915d-a48bc1ee5a4d" xlink:to="loc_us-gaap_FinanceLeaseLiabilityNoncurrent_019e78f5-a339-742c-b72b-3b211924abd5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_019e78f5-a339-74a2-ad31-87c52c6eea35" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e78f5-a339-78f2-915d-a48bc1ee5a4d" xlink:to="loc_us-gaap_Liabilities_019e78f5-a339-74a2-ad31-87c52c6eea35" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityAbstract_019e78f5-a339-7915-ae0d-8e69ced65ef0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e78f5-a339-78f2-915d-a48bc1ee5a4d" xlink:to="loc_us-gaap_StockholdersEquityAbstract_019e78f5-a339-7915-ae0d-8e69ced65ef0" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockValueOutstanding_019e78f5-a339-73dd-9074-de3053f369fe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockValueOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e78f5-a339-7915-ae0d-8e69ced65ef0" xlink:to="loc_us-gaap_PreferredStockValueOutstanding_019e78f5-a339-73dd-9074-de3053f369fe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_019e78f5-a339-7bf0-a7e1-865d9859aa61" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e78f5-a339-7915-ae0d-8e69ced65ef0" xlink:to="loc_us-gaap_CommonStockValue_019e78f5-a339-7bf0-a7e1-865d9859aa61" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapital_019e78f5-a339-7ca4-b239-cc2c3e458381" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e78f5-a339-7915-ae0d-8e69ced65ef0" xlink:to="loc_us-gaap_AdditionalPaidInCapital_019e78f5-a339-7ca4-b239-cc2c3e458381" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019e78f5-a339-7960-8044-ee557e8dbd81" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e78f5-a339-7915-ae0d-8e69ced65ef0" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019e78f5-a339-7960-8044-ee557e8dbd81" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019e78f5-a339-7dbd-bb0d-2b4e04d149ab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e78f5-a339-7915-ae0d-8e69ced65ef0" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019e78f5-a339-7dbd-bb0d-2b4e04d149ab" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonValue_019e78f5-a339-76da-8949-010cb86e2d98" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockCommonValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e78f5-a339-7915-ae0d-8e69ced65ef0" xlink:to="loc_us-gaap_TreasuryStockCommonValue_019e78f5-a339-76da-8949-010cb86e2d98" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e78f5-a339-7d5f-8b90-793d7b540096" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e78f5-a339-7915-ae0d-8e69ced65ef0" xlink:to="loc_us-gaap_StockholdersEquity_019e78f5-a339-7d5f-8b90-793d7b540096" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_019e78f5-a339-76b9-9093-13b0e2c2d59e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e78f5-a339-78f2-915d-a48bc1ee5a4d" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_019e78f5-a339-76b9-9093-13b0e2c2d59e" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/UNAUDITEDCONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical" xlink:type="simple" xlink:href="ftk-20260630.xsd#UNAUDITEDCONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/UNAUDITEDCONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e78f5-a3fb-71bc-8228-6d25f4edd867" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e78f5-a3fb-70f5-9519-7ae8c7f8efd7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-71bc-8228-6d25f4edd867" xlink:to="loc_us-gaap_StatementTable_019e78f5-a3fb-70f5-9519-7ae8c7f8efd7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a3fb-785c-a592-915f67afb35a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e78f5-a3fb-70f5-9519-7ae8c7f8efd7" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a3fb-785c-a592-915f67afb35a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e78f5-a3fb-785c-a592-915f67afb35a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a3fb-785c-a592-915f67afb35a" xlink:to="loc_us-gaap_RelatedPartyDomain_019e78f5-a3fb-785c-a592-915f67afb35a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e78f5-a3fb-707c-978d-bf1bcb65adf2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a3fb-785c-a592-915f67afb35a" xlink:to="loc_us-gaap_RelatedPartyDomain_019e78f5-a3fb-707c-978d-bf1bcb65adf2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonrelatedPartyMember_019e78f5-a3fb-7ef9-be52-fc5ea0003dd5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonrelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e78f5-a3fb-707c-978d-bf1bcb65adf2" xlink:to="loc_us-gaap_NonrelatedPartyMember_019e78f5-a3fb-7ef9-be52-fc5ea0003dd5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019e78f5-a3fb-7b79-af0d-3ed65fc1d7ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e78f5-a3fb-707c-978d-bf1bcb65adf2" xlink:to="loc_us-gaap_RelatedPartyMember_019e78f5-a3fb-7b79-af0d-3ed65fc1d7ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_019e78f5-a3fb-7d85-9598-6e2b02635027" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-71bc-8228-6d25f4edd867" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_019e78f5-a3fb-7d85-9598-6e2b02635027" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_019e78f5-a3fb-7203-8c0e-18da4087942d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-71bc-8228-6d25f4edd867" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_019e78f5-a3fb-7203-8c0e-18da4087942d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_019e78f5-a3fb-746c-8eac-92bba3b0e689" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-71bc-8228-6d25f4edd867" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_019e78f5-a3fb-746c-8eac-92bba3b0e689" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesIssued_019e78f5-a3fb-7cd2-880b-492759776f86" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-71bc-8228-6d25f4edd867" xlink:to="loc_us-gaap_PreferredStockSharesIssued_019e78f5-a3fb-7cd2-880b-492759776f86" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_019e78f5-a3fb-7a9b-9efc-d0a670b860e6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-71bc-8228-6d25f4edd867" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_019e78f5-a3fb-7a9b-9efc-d0a670b860e6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_019e78f5-a3fb-76cc-8f3c-8e945cf0794c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-71bc-8228-6d25f4edd867" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_019e78f5-a3fb-76cc-8f3c-8e945cf0794c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_019e78f5-a3fb-73e3-8715-5197bb7f2f72" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-71bc-8228-6d25f4edd867" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_019e78f5-a3fb-73e3-8715-5197bb7f2f72" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_019e78f5-a3fb-78a3-98d5-6ce7f0d12553" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-71bc-8228-6d25f4edd867" xlink:to="loc_us-gaap_CommonStockSharesIssued_019e78f5-a3fb-78a3-98d5-6ce7f0d12553" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019e78f5-a3fb-7abe-84b4-ba1a108dcc2a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-71bc-8228-6d25f4edd867" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_019e78f5-a3fb-7abe-84b4-ba1a108dcc2a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonShares_019e78f5-a3fb-7b6a-b311-dd46169d3192" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockCommonShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-71bc-8228-6d25f4edd867" xlink:to="loc_us-gaap_TreasuryStockCommonShares_019e78f5-a3fb-7b6a-b311-dd46169d3192" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/UNAUDITEDCONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONS" xlink:type="simple" xlink:href="ftk-20260630.xsd#UNAUDITEDCONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONS"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/UNAUDITEDCONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONS" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e78f5-a3fb-798c-92b1-c42b1dfc362e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e78f5-a3fb-7c4c-bf9b-96e86c2905b9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-798c-92b1-c42b1dfc362e" xlink:to="loc_us-gaap_StatementTable_019e78f5-a3fb-7c4c-bf9b-96e86c2905b9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a3fb-73ff-9929-08b59085b697" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e78f5-a3fb-7c4c-bf9b-96e86c2905b9" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a3fb-73ff-9929-08b59085b697" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e78f5-a3fb-73ff-9929-08b59085b697_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a3fb-73ff-9929-08b59085b697" xlink:to="loc_us-gaap_RelatedPartyDomain_019e78f5-a3fb-73ff-9929-08b59085b697_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e78f5-a3fb-7619-98e0-0a3d2b116831" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a3fb-73ff-9929-08b59085b697" xlink:to="loc_us-gaap_RelatedPartyDomain_019e78f5-a3fb-7619-98e0-0a3d2b116831" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonrelatedPartyMember_019e78f5-a3fb-7542-8ff2-62e4968ca2df" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonrelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e78f5-a3fb-7619-98e0-0a3d2b116831" xlink:to="loc_us-gaap_NonrelatedPartyMember_019e78f5-a3fb-7542-8ff2-62e4968ca2df" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019e78f5-a3fb-7954-8715-902d1fc33623" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e78f5-a3fb-7619-98e0-0a3d2b116831" xlink:to="loc_us-gaap_RelatedPartyMember_019e78f5-a3fb-7954-8715-902d1fc33623" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_019e78f5-a3fb-732d-9e5f-b85c66fd5763" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenuesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-798c-92b1-c42b1dfc362e" xlink:to="loc_us-gaap_RevenuesAbstract_019e78f5-a3fb-732d-9e5f-b85c66fd5763" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e78f5-a3fb-7f74-b7da-8fbaf06ae4d2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_019e78f5-a3fb-732d-9e5f-b85c66fd5763" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e78f5-a3fb-7f74-b7da-8fbaf06ae4d2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_019e78f5-a3fb-7ed8-bb4a-f78aeb0e7b3c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-798c-92b1-c42b1dfc362e" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_019e78f5-a3fb-7ed8-bb4a-f78aeb0e7b3c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_019e78f5-a3fb-7b17-8f09-3eea6329f668" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GrossProfit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-798c-92b1-c42b1dfc362e" xlink:to="loc_us-gaap_GrossProfit_019e78f5-a3fb-7b17-8f09-3eea6329f668" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpensesAbstract_019e78f5-a3fb-7704-aa84-8249cb56d231" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostsAndExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-798c-92b1-c42b1dfc362e" xlink:to="loc_us-gaap_CostsAndExpensesAbstract_019e78f5-a3fb-7704-aa84-8249cb56d231" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_019e78f5-a3fb-72d1-8d3d-1c354f65fe53" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_019e78f5-a3fb-7704-aa84-8249cb56d231" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_019e78f5-a3fb-72d1-8d3d-1c354f65fe53" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_AssetAcquisitionTransactionCosts_019f44b8-df1c-7bb2-96c1-5fa1ae69db05" xlink:href="ftk-20260630.xsd#ftk_AssetAcquisitionTransactionCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_019e78f5-a3fb-7704-aa84-8249cb56d231" xlink:to="loc_ftk_AssetAcquisitionTransactionCosts_019f44b8-df1c-7bb2-96c1-5fa1ae69db05" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_019e78f5-a3fb-7104-9975-506e6c54c221" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Depreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_019e78f5-a3fb-7704-aa84-8249cb56d231" xlink:to="loc_us-gaap_Depreciation_019e78f5-a3fb-7104-9975-506e6c54c221" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_019e78f5-a3fb-7213-a8d1-3da9eb880808" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_019e78f5-a3fb-7704-aa84-8249cb56d231" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_019e78f5-a3fb-7213-a8d1-3da9eb880808" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_019e78f5-a3fb-7056-a56b-06afe2267e2d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnSaleOfPropertyPlantEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_019e78f5-a3fb-7704-aa84-8249cb56d231" xlink:to="loc_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_019e78f5-a3fb-7056-a56b-06afe2267e2d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpenses_019e78f5-a3fb-7153-8dc0-170e01f7dde1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostsAndExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_019e78f5-a3fb-7704-aa84-8249cb56d231" xlink:to="loc_us-gaap_CostsAndExpenses_019e78f5-a3fb-7153-8dc0-170e01f7dde1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_019e78f5-a3fb-76c3-b85a-d297fc451069" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-798c-92b1-c42b1dfc362e" xlink:to="loc_us-gaap_OperatingIncomeLoss_019e78f5-a3fb-76c3-b85a-d297fc451069" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpenseAbstract_019e78f5-a3fb-7d13-a6a0-c2725c07f740" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonoperatingIncomeExpenseAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-798c-92b1-c42b1dfc362e" xlink:to="loc_us-gaap_NonoperatingIncomeExpenseAbstract_019e78f5-a3fb-7d13-a6a0-c2725c07f740" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseNonoperating_019e78f5-a3fb-7489-b560-008e4af65d71" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseNonoperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_019e78f5-a3fb-7d13-a6a0-c2725c07f740" xlink:to="loc_us-gaap_InterestExpenseNonoperating_019e78f5-a3fb-7489-b560-008e4af65d71" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_019e78f5-a3fb-7050-8971-45587cff5195" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_019e78f5-a3fb-7d13-a6a0-c2725c07f740" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_019e78f5-a3fb-7050-8971-45587cff5195" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_019e78f5-a3fb-7d1b-a2a5-e224d155241b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_019e78f5-a3fb-7d13-a6a0-c2725c07f740" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_019e78f5-a3fb-7d1b-a2a5-e224d155241b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e78f5-a3fb-78e6-bd24-c9423300cdec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-798c-92b1-c42b1dfc362e" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e78f5-a3fb-78e6-bd24-c9423300cdec" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_019e78f5-a3fb-7e60-8c68-2130a6c45125" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-798c-92b1-c42b1dfc362e" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_019e78f5-a3fb-7e60-8c68-2130a6c45125" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e78f5-a3fb-7758-81eb-64b79179bc44" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-798c-92b1-c42b1dfc362e" xlink:to="loc_us-gaap_NetIncomeLoss_019e78f5-a3fb-7758-81eb-64b79179bc44" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_019e78f5-a3fb-7825-82e6-6aa410d25740" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-798c-92b1-c42b1dfc362e" xlink:to="loc_us-gaap_EarningsPerShareAbstract_019e78f5-a3fb-7825-82e6-6aa410d25740" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_019e78f5-a3fb-72c2-a86d-51437313a147" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_019e78f5-a3fb-7825-82e6-6aa410d25740" xlink:to="loc_us-gaap_EarningsPerShareBasic_019e78f5-a3fb-72c2-a86d-51437313a147" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_019e78f5-a3fc-7c19-8004-9190ba43a711" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_019e78f5-a3fb-7825-82e6-6aa410d25740" xlink:to="loc_us-gaap_EarningsPerShareDiluted_019e78f5-a3fc-7c19-8004-9190ba43a711" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019e78f5-a3fc-77d8-95b6-2101aa33991c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fb-798c-92b1-c42b1dfc362e" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019e78f5-a3fc-77d8-95b6-2101aa33991c" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019e78f5-a3fc-77b6-83b3-1939c8f6bc5a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019e78f5-a3fc-77d8-95b6-2101aa33991c" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019e78f5-a3fc-77b6-83b3-1939c8f6bc5a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019e78f5-a3fc-7858-a246-5cc8fc196575" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019e78f5-a3fc-77d8-95b6-2101aa33991c" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019e78f5-a3fc-7858-a246-5cc8fc196575" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/UNAUDITEDCONDENSEDCONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITY" xlink:type="simple" xlink:href="ftk-20260630.xsd#UNAUDITEDCONDENSEDCONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITY"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/UNAUDITEDCONDENSEDCONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITY" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e78f5-a3fc-7100-9b86-b0ce54e48970" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e78f5-a3fc-7189-953a-ed8040a32aa0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fc-7100-9b86-b0ce54e48970" xlink:to="loc_us-gaap_StatementTable_019e78f5-a3fc-7189-953a-ed8040a32aa0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019e78f5-a3fc-7322-8fda-ccc19612e37a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e78f5-a3fc-7189-953a-ed8040a32aa0" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019e78f5-a3fc-7322-8fda-ccc19612e37a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e78f5-a3fc-7322-8fda-ccc19612e37a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e78f5-a3fc-7322-8fda-ccc19612e37a" xlink:to="loc_us-gaap_EquityComponentDomain_019e78f5-a3fc-7322-8fda-ccc19612e37a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e78f5-a3fc-76a7-890c-3e6c12a7435f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e78f5-a3fc-7322-8fda-ccc19612e37a" xlink:to="loc_us-gaap_EquityComponentDomain_019e78f5-a3fc-76a7-890c-3e6c12a7435f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019e78f5-a3fc-7a7a-ba37-0ad13c2dafaf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e78f5-a3fc-76a7-890c-3e6c12a7435f" xlink:to="loc_us-gaap_CommonStockMember_019e78f5-a3fc-7a7a-ba37-0ad13c2dafaf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonMember_019e78f5-a3fc-75bd-981f-4ea128c88c80" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockCommonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e78f5-a3fc-76a7-890c-3e6c12a7435f" xlink:to="loc_us-gaap_TreasuryStockCommonMember_019e78f5-a3fc-75bd-981f-4ea128c88c80" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_019e78f5-a3fc-7110-9e07-2c19f0d70f28" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e78f5-a3fc-76a7-890c-3e6c12a7435f" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_019e78f5-a3fc-7110-9e07-2c19f0d70f28" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e78f5-a3fc-73a6-afb3-4c37050641c5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e78f5-a3fc-76a7-890c-3e6c12a7435f" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e78f5-a3fc-73a6-afb3-4c37050641c5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_019e78f5-a3fc-724a-a5fc-7779a46b5ec8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e78f5-a3fc-76a7-890c-3e6c12a7435f" xlink:to="loc_us-gaap_RetainedEarningsMember_019e78f5-a3fc-724a-a5fc-7779a46b5ec8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e78f5-a3fc-7100-9b86-b0ce54e48970" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_019e78f5-a3fc-77db-9435-e04bfa5aaa2d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:to="loc_us-gaap_CommonStockSharesIssued_019e78f5-a3fc-77db-9435-e04bfa5aaa2d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e78f5-a3fc-7bef-8dad-69d471b08226" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:to="loc_us-gaap_StockholdersEquity_019e78f5-a3fc-7bef-8dad-69d471b08226" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonShares_019e78f5-a3fc-7430-a87f-d75e555c0926" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockCommonShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:to="loc_us-gaap_TreasuryStockCommonShares_019e78f5-a3fc-7430-a87f-d75e555c0926" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e78f5-a3fc-7934-82ab-d4b621c3450b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:to="loc_us-gaap_NetIncomeLoss_019e78f5-a3fc-7934-82ab-d4b621c3450b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_019e78f5-a3fc-70bc-add2-70b00262c2e8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_019e78f5-a3fc-70bc-add2-70b00262c2e8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_019e78f5-a3fc-7d24-8f15-56fc49b7bae8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_019e78f5-a3fc-7d24-8f15-56fc49b7bae8" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_019e78f5-a3fc-7b82-b766-48bfec434065" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_019e78f5-a3fc-7b82-b766-48bfec434065" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_019e78f5-a3fc-7135-aafa-e14fbd105448" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_019e78f5-a3fc-7135-aafa-e14fbd105448" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_019e78f5-a3fc-74ea-b058-07f024fa7861" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_019e78f5-a3fc-74ea-b058-07f024fa7861" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_019e78f5-a3fc-77d0-a990-18d359c837df" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_019e78f5-a3fc-77d0-a990-18d359c837df" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardForfeited_019f89f3-b7b6-79ca-bcf7-a6a63a24ea99" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardForfeited"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardForfeited_019f89f3-b7b6-79ca-bcf7-a6a63a24ea99" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_StockIssuedDuringPeriodSharesRestrictedStockAwardVested_019e78f5-a3fc-7f66-918a-a53fed1afb9e" xlink:href="ftk-20260630.xsd#ftk_StockIssuedDuringPeriodSharesRestrictedStockAwardVested"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:to="loc_ftk_StockIssuedDuringPeriodSharesRestrictedStockAwardVested_019e78f5-a3fc-7f66-918a-a53fed1afb9e" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_019e78f5-a3fc-792a-983d-a5e6d40eb760" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_019e78f5-a3fc-792a-983d-a5e6d40eb760" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_019e78f5-a3fc-746c-a4af-7700fe5c536f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:to="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_019e78f5-a3fc-746c-a4af-7700fe5c536f" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_019e78f5-a3fc-70ae-bdcc-81f4ef093d68" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:to="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_019e78f5-a3fc-70ae-bdcc-81f4ef093d68" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_StockIssuedDuringPeriodSharesWarrants_019e78f5-a3fc-794f-a206-4424a0eba513" xlink:href="ftk-20260630.xsd#ftk_StockIssuedDuringPeriodSharesWarrants"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:to="loc_ftk_StockIssuedDuringPeriodSharesWarrants_019e78f5-a3fc-794f-a206-4424a0eba513" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_StockIssuedDuringPeriodValueWarrants_019ea665-6891-7b16-afba-e9863c474c10" xlink:href="ftk-20260630.xsd#ftk_StockIssuedDuringPeriodValueWarrants"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:to="loc_ftk_StockIssuedDuringPeriodValueWarrants_019ea665-6891-7b16-afba-e9863c474c10" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_StockIssuedDuringPeriodValueExcessConsiderationOverAssetBookValue_019f89e8-ca86-7f6e-914f-6fbc305cd862" xlink:href="ftk-20260630.xsd#ftk_StockIssuedDuringPeriodValueExcessConsiderationOverAssetBookValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:to="loc_ftk_StockIssuedDuringPeriodValueExcessConsiderationOverAssetBookValue_019f89e8-ca86-7f6e-914f-6fbc305cd862" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued_019f89e9-86a8-7170-bdb3-5c57ae36a617" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e78f5-a3fc-7f4d-90cf-acd995319c41" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued_019f89e9-86a8-7170-bdb3-5c57ae36a617" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_019e78f5-a3fc-730a-9e35-a3016741fca2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e78f5-a3fc-73c3-a5f3-327707effe22" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonShares_019e78f5-a3fc-7eea-9f83-0af41ba384da" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockCommonShares"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/RevenuefromContractswithCustomersDisaggregationofRevenueDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#RevenuefromContractswithCustomersDisaggregationofRevenueDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/RevenuefromContractswithCustomersDisaggregationofRevenueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_019e78f5-a3fc-7f09-a11c-61d4b82c08bb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_019e78f5-a3fc-74d3-b61c-743431398924" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019e78f5-a3fc-7f09-a11c-61d4b82c08bb" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_019e78f5-a3fc-74d3-b61c-743431398924" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019e78f5-a3fc-7557-bf66-67d25e1aee5d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019e78f5-a3fc-74d3-b61c-743431398924" xlink:to="loc_srt_ProductOrServiceAxis_019e78f5-a3fc-7557-bf66-67d25e1aee5d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019e78f5-a3fc-7557-bf66-67d25e1aee5d_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019e78f5-a3fc-7557-bf66-67d25e1aee5d" xlink:to="loc_srt_ProductsAndServicesDomain_019e78f5-a3fc-7557-bf66-67d25e1aee5d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019e78f5-a3fc-7027-987f-d3fc5ee3a900" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019e78f5-a3fc-7557-bf66-67d25e1aee5d" xlink:to="loc_srt_ProductsAndServicesDomain_019e78f5-a3fc-7027-987f-d3fc5ee3a900" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_019e78f5-a3fc-78c9-9365-101739b432b6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e78f5-a3fc-7027-987f-d3fc5ee3a900" xlink:to="loc_us-gaap_ProductMember_019e78f5-a3fc-78c9-9365-101739b432b6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ServiceMember_019e78f5-a3fc-796d-a340-5e36651bc7dc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ServiceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e78f5-a3fc-7027-987f-d3fc5ee3a900" xlink:to="loc_us-gaap_ServiceMember_019e78f5-a3fc-796d-a340-5e36651bc7dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_RentalMember_019e78f5-a3fc-785c-84cd-46a632d4d9a8" xlink:href="ftk-20260630.xsd#ftk_RentalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e78f5-a3fc-7027-987f-d3fc5ee3a900" xlink:to="loc_ftk_RentalMember_019e78f5-a3fc-785c-84cd-46a632d4d9a8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e78f5-a3fc-78e1-8fa7-206a88d655d0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019e78f5-a3fc-7f09-a11c-61d4b82c08bb" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e78f5-a3fc-78e1-8fa7-206a88d655d0" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/RevenuefromContractswithCustomersCostofRevenueDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#RevenuefromContractswithCustomersCostofRevenueDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/RevenuefromContractswithCustomersCostofRevenueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_019e78f5-a3fc-7b13-8df9-1e2621a23328" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_019e78f5-a3fc-781e-9b5b-a412c927f516" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019e78f5-a3fc-7b13-8df9-1e2621a23328" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_019e78f5-a3fc-781e-9b5b-a412c927f516" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019e78f5-a3fc-7af3-92e4-00dc5ec241b3" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019e78f5-a3fc-781e-9b5b-a412c927f516" xlink:to="loc_srt_ProductOrServiceAxis_019e78f5-a3fc-7af3-92e4-00dc5ec241b3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019e78f5-a3fc-7af3-92e4-00dc5ec241b3_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019e78f5-a3fc-7af3-92e4-00dc5ec241b3" xlink:to="loc_srt_ProductsAndServicesDomain_019e78f5-a3fc-7af3-92e4-00dc5ec241b3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019e78f5-a3fc-70bd-9b36-59025104f638" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019e78f5-a3fc-7af3-92e4-00dc5ec241b3" xlink:to="loc_srt_ProductsAndServicesDomain_019e78f5-a3fc-70bd-9b36-59025104f638" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_019e78f5-a3fc-7c7a-9d3a-2032f126c556" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e78f5-a3fc-70bd-9b36-59025104f638" xlink:to="loc_us-gaap_ProductMember_019e78f5-a3fc-7c7a-9d3a-2032f126c556" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ServiceMember_019e78f5-a3fc-7657-9353-96107b265737" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ServiceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e78f5-a3fc-70bd-9b36-59025104f638" xlink:to="loc_us-gaap_ServiceMember_019e78f5-a3fc-7657-9353-96107b265737" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductAndServiceOtherMember_019e78f5-a3fc-7a50-9411-8a253c8087f0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProductAndServiceOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e78f5-a3fc-70bd-9b36-59025104f638" xlink:to="loc_us-gaap_ProductAndServiceOtherMember_019e78f5-a3fc-7a50-9411-8a253c8087f0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a3fc-7c31-828d-7c1a14a3305e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019e78f5-a3fc-781e-9b5b-a412c927f516" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a3fc-7c31-828d-7c1a14a3305e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e78f5-a3fc-7c31-828d-7c1a14a3305e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a3fc-7c31-828d-7c1a14a3305e" xlink:to="loc_us-gaap_RelatedPartyDomain_019e78f5-a3fc-7c31-828d-7c1a14a3305e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e78f5-a3fc-7c8d-aafc-6a5500b3280a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a3fc-7c31-828d-7c1a14a3305e" xlink:to="loc_us-gaap_RelatedPartyDomain_019e78f5-a3fc-7c8d-aafc-6a5500b3280a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonrelatedPartyMember_019e78f5-a3fc-798b-87a5-226efb2cad3f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonrelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e78f5-a3fc-7c8d-aafc-6a5500b3280a" xlink:to="loc_us-gaap_NonrelatedPartyMember_019e78f5-a3fc-798b-87a5-226efb2cad3f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019e78f5-a3fc-71a5-9b29-2d7dcf396141" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e78f5-a3fc-7c8d-aafc-6a5500b3280a" xlink:to="loc_us-gaap_RelatedPartyMember_019e78f5-a3fc-71a5-9b29-2d7dcf396141" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_019e78f5-a3fc-7c63-bab2-8bbadb950d00" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019e78f5-a3fc-7b13-8df9-1e2621a23328" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_019e78f5-a3fc-7c63-bab2-8bbadb950d00" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCostOfOperatingRevenue_019e78f5-a3fc-72fe-a42c-e3ecd65fa8da" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherCostOfOperatingRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019e78f5-a3fc-7b13-8df9-1e2621a23328" xlink:to="loc_us-gaap_OtherCostOfOperatingRevenue_019e78f5-a3fc-72fe-a42c-e3ecd65fa8da" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/ContractAssetsNarrativeDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#ContractAssetsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/ContractAssetsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_019e78f5-a3fc-7ee4-822c-493178f0bd80" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_019e78f5-a3fc-7c5b-989e-10373bf3efdc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019e78f5-a3fc-7ee4-822c-493178f0bd80" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_019e78f5-a3fc-7c5b-989e-10373bf3efdc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_019e78f5-a3fc-7404-bb15-50d53f08a80a" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019e78f5-a3fc-7c5b-989e-10373bf3efdc" xlink:to="loc_srt_MajorCustomersAxis_019e78f5-a3fc-7404-bb15-50d53f08a80a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_019e78f5-a3fc-7404-bb15-50d53f08a80a_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_019e78f5-a3fc-7404-bb15-50d53f08a80a" xlink:to="loc_srt_NameOfMajorCustomerDomain_019e78f5-a3fc-7404-bb15-50d53f08a80a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_019e78f5-a3fc-7def-9867-814a960e3c01" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_019e78f5-a3fc-7404-bb15-50d53f08a80a" xlink:to="loc_srt_NameOfMajorCustomerDomain_019e78f5-a3fc-7def-9867-814a960e3c01" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_ProFracAgreementMember_019e78f5-a3fc-7de0-8056-1487cbb46b0a" xlink:href="ftk-20260630.xsd#ftk_ProFracAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_019e78f5-a3fc-7def-9867-814a960e3c01" xlink:to="loc_ftk_ProFracAgreementMember_019e78f5-a3fc-7de0-8056-1487cbb46b0a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetGross_019e78f5-a3fc-76aa-925c-9ae498cb5734" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerAssetGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019e78f5-a3fc-7ee4-822c-493178f0bd80" xlink:to="loc_us-gaap_ContractWithCustomerAssetGross_019e78f5-a3fc-76aa-925c-9ae498cb5734" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostNet_019e78f5-a3fc-7ce3-b66a-29908e6b9ff3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizedContractCostNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019e78f5-a3fc-7ee4-822c-493178f0bd80" xlink:to="loc_us-gaap_CapitalizedContractCostNet_019e78f5-a3fc-7ce3-b66a-29908e6b9ff3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetNetNoncurrent_019e78f5-a3fc-702a-ac02-ca7bac62b9ff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerAssetNetNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019e78f5-a3fc-7ee4-822c-493178f0bd80" xlink:to="loc_us-gaap_ContractWithCustomerAssetNetNoncurrent_019e78f5-a3fc-702a-ac02-ca7bac62b9ff" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostAmortization_019e78f5-a3fc-7af1-9abc-93af552b6e90" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizedContractCostAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019e78f5-a3fc-7ee4-822c-493178f0bd80" xlink:to="loc_us-gaap_CapitalizedContractCostAmortization_019e78f5-a3fc-7af1-9abc-93af552b6e90" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/InventoriesNarrativeDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#InventoriesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/InventoriesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryLineItems_019e78f5-a3fc-7c67-a248-150e2c79f154" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryCurrentTable_019e78f5-a3fc-725d-8257-9e449881e680" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryCurrentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_InventoryLineItems_019e78f5-a3fc-7c67-a248-150e2c79f154" xlink:to="loc_us-gaap_InventoryCurrentTable_019e78f5-a3fc-725d-8257-9e449881e680" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019e78f5-a3fc-7b90-a6da-1fa613226ab5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_InventoryCurrentTable_019e78f5-a3fc-725d-8257-9e449881e680" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019e78f5-a3fc-7b90-a6da-1fa613226ab5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e78f5-a3fc-7b90-a6da-1fa613226ab5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e78f5-a3fc-7b90-a6da-1fa613226ab5" xlink:to="loc_us-gaap_SegmentDomain_019e78f5-a3fc-7b90-a6da-1fa613226ab5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e78f5-a3fc-7b69-b079-c22ec9a01bba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e78f5-a3fc-7b90-a6da-1fa613226ab5" xlink:to="loc_us-gaap_SegmentDomain_019e78f5-a3fc-7b69-b079-c22ec9a01bba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_ChemistryTechnologiesSegmentMember_019e78f5-a3fc-73ae-82af-6f6f5b082a14" xlink:href="ftk-20260630.xsd#ftk_ChemistryTechnologiesSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e78f5-a3fc-7b69-b079-c22ec9a01bba" xlink:to="loc_ftk_ChemistryTechnologiesSegmentMember_019e78f5-a3fc-73ae-82af-6f6f5b082a14" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_DataAnalyticsSegmentMember_019e78f5-a3fc-7a62-8c0c-667caa0c1af4" xlink:href="ftk-20260630.xsd#ftk_DataAnalyticsSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e78f5-a3fc-7b69-b079-c22ec9a01bba" xlink:to="loc_ftk_DataAnalyticsSegmentMember_019e78f5-a3fc-7a62-8c0c-667caa0c1af4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_InventoryValuationProvision_019e78f5-a3fc-7acb-8658-5ef8592c236d" xlink:href="ftk-20260630.xsd#ftk_InventoryValuationProvision"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryLineItems_019e78f5-a3fc-7c67-a248-150e2c79f154" xlink:to="loc_ftk_InventoryValuationProvision_019e78f5-a3fc-7acb-8658-5ef8592c236d" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/PropertyandEquipmentComponentsofPropertyandEquipmentDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#PropertyandEquipmentComponentsofPropertyandEquipmentDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/PropertyandEquipmentComponentsofPropertyandEquipmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e78f5-a3fc-76d1-9246-6e7fc132679e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019e78f5-a3fc-722e-a4fe-954e54f42721" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e78f5-a3fc-76d1-9246-6e7fc132679e" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019e78f5-a3fc-722e-a4fe-954e54f42721" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019e78f5-a3fc-7b32-82fd-5113d15ead71" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019e78f5-a3fc-722e-a4fe-954e54f42721" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019e78f5-a3fc-7b32-82fd-5113d15ead71" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e78f5-a3fc-7b32-82fd-5113d15ead71_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019e78f5-a3fc-7b32-82fd-5113d15ead71" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e78f5-a3fc-7b32-82fd-5113d15ead71_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e78f5-a3fc-7795-b680-362446806a4c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019e78f5-a3fc-7b32-82fd-5113d15ead71" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e78f5-a3fc-7795-b680-362446806a4c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandMember_019e78f5-a3fc-7d80-bb16-ecf2fcca7b87" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LandMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e78f5-a3fc-7795-b680-362446806a4c" xlink:to="loc_us-gaap_LandMember_019e78f5-a3fc-7d80-bb16-ecf2fcca7b87" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandImprovementsMember_019e78f5-a3fc-7a3c-bc06-2fa0a3ff0884" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LandImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e78f5-a3fc-7795-b680-362446806a4c" xlink:to="loc_us-gaap_LandImprovementsMember_019e78f5-a3fc-7a3c-bc06-2fa0a3ff0884" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_BuildingAndLeaseholdMemberMember_019e78f5-a3fc-72b5-92d0-8a855e1a3052" xlink:href="ftk-20260630.xsd#ftk_BuildingAndLeaseholdMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e78f5-a3fc-7795-b680-362446806a4c" xlink:to="loc_ftk_BuildingAndLeaseholdMemberMember_019e78f5-a3fc-72b5-92d0-8a855e1a3052" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MachineryAndEquipmentMember_019e78f5-a3fc-7f51-ab6e-c5bfc5902ecf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MachineryAndEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e78f5-a3fc-7795-b680-362446806a4c" xlink:to="loc_us-gaap_MachineryAndEquipmentMember_019e78f5-a3fc-7f51-ab6e-c5bfc5902ecf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_019e78f5-a3fc-714d-88bc-1bf9cba1fb2a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FurnitureAndFixturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e78f5-a3fc-7795-b680-362446806a4c" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_019e78f5-a3fc-714d-88bc-1bf9cba1fb2a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransportationEquipmentMember_019e78f5-a3fc-7864-bff7-5d577b066567" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransportationEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e78f5-a3fc-7795-b680-362446806a4c" xlink:to="loc_us-gaap_TransportationEquipmentMember_019e78f5-a3fc-7864-bff7-5d577b066567" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_ComputerEquipmentAndSoftwareMember_019e78f5-a3fc-7005-a798-5f68f7a840e0" xlink:href="ftk-20260630.xsd#ftk_ComputerEquipmentAndSoftwareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e78f5-a3fc-7795-b680-362446806a4c" xlink:to="loc_ftk_ComputerEquipmentAndSoftwareMember_019e78f5-a3fc-7005-a798-5f68f7a840e0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_019e78f5-a3fc-7cea-b05a-3ef8601d255f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNetAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e78f5-a3fc-76d1-9246-6e7fc132679e" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_019e78f5-a3fc-7cea-b05a-3ef8601d255f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization_019e78f5-a3fc-761c-a08c-73d359a3fba4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_019e78f5-a3fc-7cea-b05a-3ef8601d255f" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization_019e78f5-a3fc-761c-a08c-73d359a3fba4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization_019e78f5-a3fc-744b-8d52-dc196d045b92" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_019e78f5-a3fc-7cea-b05a-3ef8601d255f" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization_019e78f5-a3fc-744b-8d52-dc196d045b92" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_019e78f5-a3fc-7863-80f9-b41fee634850" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_019e78f5-a3fc-7cea-b05a-3ef8601d255f" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_019e78f5-a3fc-7863-80f9-b41fee634850" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/LeasesLeaseAgreementIncomeDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#LeasesLeaseAgreementIncomeDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/LeasesLeaseAgreementIncomeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeaseDescriptionLineItems_019e78f5-a3fc-73ab-b67c-4b382a4fc43b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LessorLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeaseDescriptionTable_019e78f5-a3fc-7df3-bad5-ccd092d386a9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LessorLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_019e78f5-a3fc-73ab-b67c-4b382a4fc43b" xlink:to="loc_us-gaap_LessorLeaseDescriptionTable_019e78f5-a3fc-7df3-bad5-ccd092d386a9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionAxis_019e78f5-a3fc-7002-9cf9-553be38a75b1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LessorLeaseDescriptionTable_019e78f5-a3fc-7df3-bad5-ccd092d386a9" xlink:to="loc_us-gaap_AssetAcquisitionAxis_019e78f5-a3fc-7002-9cf9-553be38a75b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionDomain_019e78f5-a3fc-7002-9cf9-553be38a75b1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetAcquisitionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AssetAcquisitionAxis_019e78f5-a3fc-7002-9cf9-553be38a75b1" xlink:to="loc_us-gaap_AssetAcquisitionDomain_019e78f5-a3fc-7002-9cf9-553be38a75b1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionDomain_019e78f5-a3fc-7820-a745-f8b12c269b50" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetAcquisitionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AssetAcquisitionAxis_019e78f5-a3fc-7002-9cf9-553be38a75b1" xlink:to="loc_us-gaap_AssetAcquisitionDomain_019e78f5-a3fc-7820-a745-f8b12c269b50" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_AcquiredAssetsMember_019e78f5-a3fc-728f-a8b7-9aeea51909e3" xlink:href="ftk-20260630.xsd#ftk_AcquiredAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetAcquisitionDomain_019e78f5-a3fc-7820-a745-f8b12c269b50" xlink:to="loc_ftk_AcquiredAssetsMember_019e78f5-a3fc-728f-a8b7-9aeea51909e3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019e78f5-a3fc-7475-bf5e-31384d6252ea" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LessorLeaseDescriptionTable_019e78f5-a3fc-7df3-bad5-ccd092d386a9" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019e78f5-a3fc-7475-bf5e-31384d6252ea" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019e78f5-a3fc-7475-bf5e-31384d6252ea_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019e78f5-a3fc-7475-bf5e-31384d6252ea" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019e78f5-a3fc-7475-bf5e-31384d6252ea_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019e78f5-a3fc-75db-97ef-684aec70a3bc" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019e78f5-a3fc-7475-bf5e-31384d6252ea" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019e78f5-a3fc-75db-97ef-684aec70a3bc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_OfficeAndLabSpaceInHoustonTexasMember_019e78f5-a3fc-785a-8aba-be33589f23dc" xlink:href="ftk-20260630.xsd#ftk_OfficeAndLabSpaceInHoustonTexasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019e78f5-a3fc-75db-97ef-684aec70a3bc" xlink:to="loc_ftk_OfficeAndLabSpaceInHoustonTexasMember_019e78f5-a3fc-785a-8aba-be33589f23dc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedRemainderOfFiscalYear_019e78f5-a3fc-7e6e-a882-0f3067e0d803" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedRemainderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_019e78f5-a3fc-73ab-b67c-4b382a4fc43b" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedRemainderOfFiscalYear_019e78f5-a3fc-7e6e-a882-0f3067e0d803" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths_019e78f5-a3fc-784f-9f43-4f60d49e115b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_019e78f5-a3fc-73ab-b67c-4b382a4fc43b" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths_019e78f5-a3fc-784f-9f43-4f60d49e115b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears_019e78f5-a3fc-753c-95ed-cc0318465b2b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_019e78f5-a3fc-73ab-b67c-4b382a4fc43b" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears_019e78f5-a3fc-753c-95ed-cc0318465b2b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears_019e78f5-a3fc-7a70-a9e0-8cca5fdcd64d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_019e78f5-a3fc-73ab-b67c-4b382a4fc43b" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears_019e78f5-a3fc-7a70-a9e0-8cca5fdcd64d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_LessorOperatingLeasePaymentsToBeReceivedAfterYearThree_019e78f5-a3fc-796e-8f20-eab2f4653db7" xlink:href="ftk-20260630.xsd#ftk_LessorOperatingLeasePaymentsToBeReceivedAfterYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_019e78f5-a3fc-73ab-b67c-4b382a4fc43b" xlink:to="loc_ftk_LessorOperatingLeasePaymentsToBeReceivedAfterYearThree_019e78f5-a3fc-796e-8f20-eab2f4653db7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceived_019e78f5-a3fc-78a8-9fdb-436141f61f32" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceived"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_019e78f5-a3fc-73ab-b67c-4b382a4fc43b" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceived_019e78f5-a3fc-78a8-9fdb-436141f61f32" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/DebtAssetBackedLoanNarrativeDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#DebtAssetBackedLoanNarrativeDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/DebtAssetBackedLoanNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019e78f5-a3fc-7e19-b282-d6013ea06e6a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:to="loc_us-gaap_DebtInstrumentTable_019e78f5-a3fc-7e19-b282-d6013ea06e6a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019e78f5-a3fc-7080-aaec-dd628144d549" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e78f5-a3fc-7e19-b282-d6013ea06e6a" xlink:to="loc_us-gaap_DebtInstrumentAxis_019e78f5-a3fc-7080-aaec-dd628144d549" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e78f5-a3fc-7080-aaec-dd628144d549_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e78f5-a3fc-7080-aaec-dd628144d549" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e78f5-a3fc-7080-aaec-dd628144d549_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e78f5-a3fc-7750-9a29-78277102d6ff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e78f5-a3fc-7080-aaec-dd628144d549" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e78f5-a3fc-7750-9a29-78277102d6ff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_AssetBasedLoanMember_019e78f5-a3fc-795e-9b57-1a6ea1aab2c8" xlink:href="ftk-20260630.xsd#ftk_AssetBasedLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e78f5-a3fc-7750-9a29-78277102d6ff" xlink:to="loc_ftk_AssetBasedLoanMember_019e78f5-a3fc-795e-9b57-1a6ea1aab2c8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_019e78f5-a3fc-7ea5-b97f-8af5890d6efa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e78f5-a3fc-7750-9a29-78277102d6ff" xlink:to="loc_us-gaap_SecuredDebtMember_019e78f5-a3fc-7ea5-b97f-8af5890d6efa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_PWRTEKNoteMember_019e78f5-a3fc-7d9f-b578-05aaa1a5cdb1" xlink:href="ftk-20260630.xsd#ftk_PWRTEKNoteMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e78f5-a3fc-7750-9a29-78277102d6ff" xlink:to="loc_ftk_PWRTEKNoteMember_019e78f5-a3fc-7d9f-b578-05aaa1a5cdb1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e78f5-a3fc-7ee3-b6f4-4cbf4745b355" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e78f5-a3fc-7e19-b282-d6013ea06e6a" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e78f5-a3fc-7ee3-b6f4-4cbf4745b355" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e78f5-a3fc-7ee3-b6f4-4cbf4745b355_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e78f5-a3fc-7ee3-b6f4-4cbf4745b355" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e78f5-a3fc-7ee3-b6f4-4cbf4745b355_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e78f5-a3fc-7b39-bd6c-d312ecef95ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e78f5-a3fc-7ee3-b6f4-4cbf4745b355" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e78f5-a3fc-7b39-bd6c-d312ecef95ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_019e78f5-a3fc-71b7-a3f4-0f2b448997cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e78f5-a3fc-7b39-bd6c-d312ecef95ca" xlink:to="loc_us-gaap_LineOfCreditMember_019e78f5-a3fc-71b7-a3f4-0f2b448997cb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_019e78f5-a3fc-7d59-b70b-4d4dfb4f7af9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e78f5-a3fc-7b39-bd6c-d312ecef95ca" xlink:to="loc_us-gaap_SecuredDebtMember_019e78f5-a3fc-7d59-b70b-4d4dfb4f7af9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019e78f5-a3fc-7bfb-b1c0-843f68cbaab8" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e78f5-a3fc-7e19-b282-d6013ea06e6a" xlink:to="loc_srt_RangeAxis_019e78f5-a3fc-7bfb-b1c0-843f68cbaab8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e78f5-a3fc-7bfb-b1c0-843f68cbaab8_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019e78f5-a3fc-7bfb-b1c0-843f68cbaab8" xlink:to="loc_srt_RangeMember_019e78f5-a3fc-7bfb-b1c0-843f68cbaab8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e78f5-a3fc-77cd-8d17-70cbb1c4741e" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019e78f5-a3fc-7bfb-b1c0-843f68cbaab8" xlink:to="loc_srt_RangeMember_019e78f5-a3fc-77cd-8d17-70cbb1c4741e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019e78f5-a3fc-739b-b950-bb1c3fefe5f3" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e78f5-a3fc-77cd-8d17-70cbb1c4741e" xlink:to="loc_srt_MaximumMember_019e78f5-a3fc-739b-b950-bb1c3fefe5f3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_PeriodAxis_019e78f5-a3fc-7d34-af40-91ed67b0afda" xlink:href="ftk-20260630.xsd#ftk_PeriodAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e78f5-a3fc-7e19-b282-d6013ea06e6a" xlink:to="loc_ftk_PeriodAxis_019e78f5-a3fc-7d34-af40-91ed67b0afda" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_PeriodDomain_019e78f5-a3fc-7d34-af40-91ed67b0afda_default" xlink:href="ftk-20260630.xsd#ftk_PeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ftk_PeriodAxis_019e78f5-a3fc-7d34-af40-91ed67b0afda" xlink:to="loc_ftk_PeriodDomain_019e78f5-a3fc-7d34-af40-91ed67b0afda_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_PeriodDomain_019e78f5-a3fc-7c6f-9b0a-746ef3342cae" xlink:href="ftk-20260630.xsd#ftk_PeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ftk_PeriodAxis_019e78f5-a3fc-7d34-af40-91ed67b0afda" xlink:to="loc_ftk_PeriodDomain_019e78f5-a3fc-7c6f-9b0a-746ef3342cae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_PeriodTwoMember_019e78f5-a3fc-7923-b34f-9b5f4963da0e" xlink:href="ftk-20260630.xsd#ftk_PeriodTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ftk_PeriodDomain_019e78f5-a3fc-7c6f-9b0a-746ef3342cae" xlink:to="loc_ftk_PeriodTwoMember_019e78f5-a3fc-7923-b34f-9b5f4963da0e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_019e78f5-a3fc-770d-8439-40cd2efd0261" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e78f5-a3fc-7e19-b282-d6013ea06e6a" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_019e78f5-a3fc-770d-8439-40cd2efd0261" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_019e78f5-a3fc-770d-8439-40cd2efd0261_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_019e78f5-a3fc-770d-8439-40cd2efd0261" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_019e78f5-a3fc-770d-8439-40cd2efd0261_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_019e78f5-a3fc-78ec-b5b2-675c6186e647" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_019e78f5-a3fc-770d-8439-40cd2efd0261" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_019e78f5-a3fc-78ec-b5b2-675c6186e647" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_SecuredPromissoryNoteMember_019e78f5-a3fc-7924-aea2-7ef779f103d5" xlink:href="ftk-20260630.xsd#ftk_SecuredPromissoryNoteMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_019e78f5-a3fc-78ec-b5b2-675c6186e647" xlink:to="loc_ftk_SecuredPromissoryNoteMember_019e78f5-a3fc-7924-aea2-7ef779f103d5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_019e78f5-a3fc-77ed-8221-40b57502dd22" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:to="loc_us-gaap_DebtInstrumentTerm_019e78f5-a3fc-77ed-8221-40b57502dd22" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019e78f5-a3fc-7914-a95b-af9f8e929b8f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019e78f5-a3fc-7914-a95b-af9f8e929b8f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_LineOfCreditFacilityBorrowingBasePercentageOfEligibleAccountsReceivable_019e78f5-a3fc-75bf-b52e-cf7c2e983fd1" xlink:href="ftk-20260630.xsd#ftk_LineOfCreditFacilityBorrowingBasePercentageOfEligibleAccountsReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:to="loc_ftk_LineOfCreditFacilityBorrowingBasePercentageOfEligibleAccountsReceivable_019e78f5-a3fc-75bf-b52e-cf7c2e983fd1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_LineOfCreditFacilityBorrowingBasePercentageValueOfEligibleInventory_019e78f5-a3fc-7fa7-b37d-6b7787594939" xlink:href="ftk-20260630.xsd#ftk_LineOfCreditFacilityBorrowingBasePercentageValueOfEligibleInventory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:to="loc_ftk_LineOfCreditFacilityBorrowingBasePercentageValueOfEligibleInventory_019e78f5-a3fc-7fa7-b37d-6b7787594939" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_LineOfCreditFacilityPercentageOfRealEstateHoldings_019e78f5-a3fc-7f14-8baf-f2270379f978" xlink:href="ftk-20260630.xsd#ftk_LineOfCreditFacilityPercentageOfRealEstateHoldings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:to="loc_ftk_LineOfCreditFacilityPercentageOfRealEstateHoldings_019e78f5-a3fc-7f14-8baf-f2270379f978" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LinesOfCreditCurrent_019e78f5-a3fc-7464-9755-da8c742af723" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LinesOfCreditCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:to="loc_us-gaap_LinesOfCreditCurrent_019e78f5-a3fc-7464-9755-da8c742af723" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_019e78f5-a3fc-77e9-a012-3690104e57d0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:to="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_019e78f5-a3fc-77e9-a012-3690104e57d0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebt_019e78f5-a3fc-7ad3-84a8-74974f46088e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:to="loc_us-gaap_InterestExpenseDebt_019e78f5-a3fc-7ad3-84a8-74974f46088e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_019e78f5-a3fc-7e28-bb12-b76260e91969" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_019e78f5-a3fc-7e28-bb12-b76260e91969" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e78f5-a3fc-7c7a-bc5b-5bb6a6758e6f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e78f5-a3fc-7c7a-bc5b-5bb6a6758e6f" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019e78f5-a3fc-7331-8d33-185675150abc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019e78f5-a3fc-7331-8d33-185675150abc" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtWeightedAverageInterestRateOverTime_019e78f5-a3fc-7172-a96f-a6fecf2e1171" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtWeightedAverageInterestRateOverTime"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:to="loc_us-gaap_LongTermDebtWeightedAverageInterestRateOverTime_019e78f5-a3fc-7172-a96f-a6fecf2e1171" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_019e78f5-a3fc-7db6-acb9-01acb6dce446" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:to="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_019e78f5-a3fc-7db6-acb9-01acb6dce446" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_DebtInstrumentUnusedBorrowingCapacityFeePercentage_019e78f5-a3fc-7227-8446-e89c71a80b37" xlink:href="ftk-20260630.xsd#ftk_DebtInstrumentUnusedBorrowingCapacityFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:to="loc_ftk_DebtInstrumentUnusedBorrowingCapacityFeePercentage_019e78f5-a3fc-7227-8446-e89c71a80b37" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_LesseeOperatingLeaseEarlyTerminationFee_019f8a03-6951-7f9e-acd0-6aea508d67bc" xlink:href="ftk-20260630.xsd#ftk_LesseeOperatingLeaseEarlyTerminationFee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:to="loc_ftk_LesseeOperatingLeaseEarlyTerminationFee_019f8a03-6951-7f9e-acd0-6aea508d67bc" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_LineOfCreditFacilityEarlyTerminationFee_019e78f5-a3fc-776a-94e8-509c09d0acbc" xlink:href="ftk-20260630.xsd#ftk_LineOfCreditFacilityEarlyTerminationFee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:to="loc_ftk_LineOfCreditFacilityEarlyTerminationFee_019e78f5-a3fc-776a-94e8-509c09d0acbc" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_DebtInstrumentCovenantTangibleNetWorth_019e78f5-a3fc-7c52-9f9c-838b1c45e048" xlink:href="ftk-20260630.xsd#ftk_DebtInstrumentCovenantTangibleNetWorth"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:to="loc_ftk_DebtInstrumentCovenantTangibleNetWorth_019e78f5-a3fc-7c52-9f9c-838b1c45e048" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentIssuedPrincipal_019e78f5-a3fc-7779-9c6d-c56df5930147" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentIssuedPrincipal"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:to="loc_us-gaap_DebtInstrumentIssuedPrincipal_019e78f5-a3fc-7779-9c6d-c56df5930147" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPayableCurrent_019e78f5-a3fc-7657-aa1e-59152e2b67d7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-77a1-937a-49cd9796ebe5" xlink:to="loc_us-gaap_InterestPayableCurrent_019e78f5-a3fc-7657-aa1e-59152e2b67d7" xlink:type="arc" order="18"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/DebtScheduleofDebtDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#DebtScheduleofDebtDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/DebtScheduleofDebtDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-7f44-9c47-15b0874ac02d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019e78f5-a3fc-7513-9f83-2576794d40af" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-7f44-9c47-15b0874ac02d" xlink:to="loc_us-gaap_DebtInstrumentTable_019e78f5-a3fc-7513-9f83-2576794d40af" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e78f5-a3fc-70b8-a38e-8f57b60e2e99" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e78f5-a3fc-7513-9f83-2576794d40af" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e78f5-a3fc-70b8-a38e-8f57b60e2e99" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e78f5-a3fc-70b8-a38e-8f57b60e2e99_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e78f5-a3fc-70b8-a38e-8f57b60e2e99" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e78f5-a3fc-70b8-a38e-8f57b60e2e99_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e78f5-a3fc-74ed-9a0d-14a06121e8f0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e78f5-a3fc-70b8-a38e-8f57b60e2e99" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e78f5-a3fc-74ed-9a0d-14a06121e8f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_019e78f5-a3fc-7974-9f78-4a1e2b795686" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e78f5-a3fc-74ed-9a0d-14a06121e8f0" xlink:to="loc_us-gaap_SecuredDebtMember_019e78f5-a3fc-7974-9f78-4a1e2b795686" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019e78f5-a3fc-723d-a590-16a361cf0bd4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e78f5-a3fc-7513-9f83-2576794d40af" xlink:to="loc_us-gaap_DebtInstrumentAxis_019e78f5-a3fc-723d-a590-16a361cf0bd4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e78f5-a3fc-723d-a590-16a361cf0bd4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e78f5-a3fc-723d-a590-16a361cf0bd4" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e78f5-a3fc-723d-a590-16a361cf0bd4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e78f5-a3fc-74af-8fba-232143e64447" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e78f5-a3fc-723d-a590-16a361cf0bd4" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e78f5-a3fc-74af-8fba-232143e64447" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_PWRTEKNoteMember_019e78f5-a3fc-7092-85d6-2919c393b35c" xlink:href="ftk-20260630.xsd#ftk_PWRTEKNoteMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e78f5-a3fc-74af-8fba-232143e64447" xlink:to="loc_ftk_PWRTEKNoteMember_019e78f5-a3fc-7092-85d6-2919c393b35c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_019e78f5-a3fc-7a95-bc7c-b67d54ba44fd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-7f44-9c47-15b0874ac02d" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_019e78f5-a3fc-7a95-bc7c-b67d54ba44fd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_019e78f5-a3fc-78f8-bde6-94426214a10f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-7f44-9c47-15b0874ac02d" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_019e78f5-a3fc-78f8-bde6-94426214a10f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_019e78f5-a3fc-772d-ba56-81a1a23f8b7d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e78f5-a3fc-7f44-9c47-15b0874ac02d" xlink:to="loc_us-gaap_LongTermDebt_019e78f5-a3fc-772d-ba56-81a1a23f8b7d" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/IncomeTaxesNarrativeDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#IncomeTaxesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/IncomeTaxesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwardsLineItems_019e78f5-a4c1-747b-b78c-9810bf333381" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLossCarryforwardsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwardsTable_019e78f5-a4c1-7c15-8b03-1f89bf616f15" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLossCarryforwardsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019e78f5-a4c1-747b-b78c-9810bf333381" xlink:to="loc_us-gaap_OperatingLossCarryforwardsTable_019e78f5-a4c1-7c15-8b03-1f89bf616f15" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_019e78f5-a4c1-7d0d-80c1-d15a814d1208" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxAuthorityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OperatingLossCarryforwardsTable_019e78f5-a4c1-7c15-8b03-1f89bf616f15" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_019e78f5-a4c1-7d0d-80c1-d15a814d1208" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_019e78f5-a4c1-7d0d-80c1-d15a814d1208_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_019e78f5-a4c1-7d0d-80c1-d15a814d1208" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_019e78f5-a4c1-7d0d-80c1-d15a814d1208_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_019e78f5-a4c1-7fde-9752-bb259d43915a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_019e78f5-a4c1-7d0d-80c1-d15a814d1208" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_019e78f5-a4c1-7fde-9752-bb259d43915a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StateAndLocalJurisdictionMember_019e78f5-a4c1-7058-b9bf-89bfda98fc86" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StateAndLocalJurisdictionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_019e78f5-a4c1-7fde-9752-bb259d43915a" xlink:to="loc_us-gaap_StateAndLocalJurisdictionMember_019e78f5-a4c1-7058-b9bf-89bfda98fc86" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwards_019e78f5-a4c1-7c71-8689-0eab86746cdc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLossCarryforwards"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019e78f5-a4c1-747b-b78c-9810bf333381" xlink:to="loc_us-gaap_OperatingLossCarryforwards_019e78f5-a4c1-7c71-8689-0eab86746cdc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsSubjectToExpiration_019e78f5-a4c1-7dc1-a251-bd3beb7e2de0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsSubjectToExpiration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019e78f5-a4c1-747b-b78c-9810bf333381" xlink:to="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsSubjectToExpiration_019e78f5-a4c1-7dc1-a251-bd3beb7e2de0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_PercentageOfNetOperatingLossCarryforwardThatCanOffsetTaxableIncome_019e78f5-a4c1-77fd-b6a9-34452566a4b1" xlink:href="ftk-20260630.xsd#ftk_PercentageOfNetOperatingLossCarryforwardThatCanOffsetTaxableIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019e78f5-a4c1-747b-b78c-9810bf333381" xlink:to="loc_ftk_PercentageOfNetOperatingLossCarryforwardThatCanOffsetTaxableIncome_019e78f5-a4c1-77fd-b6a9-34452566a4b1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsNotSubjectToExpiration_019e78f5-a4c1-7952-8fb3-dc34756b2404" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsNotSubjectToExpiration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019e78f5-a4c1-747b-b78c-9810bf333381" xlink:to="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsNotSubjectToExpiration_019e78f5-a4c1-7952-8fb3-dc34756b2404" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_PercentageOfIndefiniteCarryforwardThatCanOffsetTaxableIncome_019e78f5-a4c1-77ea-b4e3-b45dbb1d29c0" xlink:href="ftk-20260630.xsd#ftk_PercentageOfIndefiniteCarryforwardThatCanOffsetTaxableIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019e78f5-a4c1-747b-b78c-9810bf333381" xlink:to="loc_ftk_PercentageOfIndefiniteCarryforwardThatCanOffsetTaxableIncome_019e78f5-a4c1-77ea-b4e3-b45dbb1d29c0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxCreditCarryforwardAmount_019e78f5-a4c1-77f0-a466-24edecfd04c9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TaxCreditCarryforwardAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019e78f5-a4c1-747b-b78c-9810bf333381" xlink:to="loc_us-gaap_TaxCreditCarryforwardAmount_019e78f5-a4c1-77f0-a466-24edecfd04c9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_OperatingLossCarryforwardsLimitationsOnUseAmount_019e78f5-a4c1-75a4-b298-84289a1e1f0c" xlink:href="ftk-20260630.xsd#ftk_OperatingLossCarryforwardsLimitationsOnUseAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019e78f5-a4c1-747b-b78c-9810bf333381" xlink:to="loc_ftk_OperatingLossCarryforwardsLimitationsOnUseAmount_019e78f5-a4c1-75a4-b298-84289a1e1f0c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_OperatingLossCarryforwardsMaximumUpliftAmount_019e78f5-a4c1-7f6b-8ab2-eb6beea991e5" xlink:href="ftk-20260630.xsd#ftk_OperatingLossCarryforwardsMaximumUpliftAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019e78f5-a4c1-747b-b78c-9810bf333381" xlink:to="loc_ftk_OperatingLossCarryforwardsMaximumUpliftAmount_019e78f5-a4c1-7f6b-8ab2-eb6beea991e5" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwardsValuationAllowance_019e78f5-a4c1-7269-b0fc-abf9c3444e16" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLossCarryforwardsValuationAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019e78f5-a4c1-747b-b78c-9810bf333381" xlink:to="loc_us-gaap_OperatingLossCarryforwardsValuationAllowance_019e78f5-a4c1-7269-b0fc-abf9c3444e16" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxCreditCarryforwardValuationAllowance_019e78f5-a4c1-762a-8515-c5ee2fee8b47" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TaxCreditCarryforwardValuationAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019e78f5-a4c1-747b-b78c-9810bf333381" xlink:to="loc_us-gaap_TaxCreditCarryforwardValuationAllowance_019e78f5-a4c1-762a-8515-c5ee2fee8b47" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/StockholdersEquityPrefundedWarrantsDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#StockholdersEquityPrefundedWarrantsDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/StockholdersEquityPrefundedWarrantsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_019e78f5-a4c1-73aa-b150-0feb2b8f64d4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_019e78f5-a4c1-709e-b0bb-cf02461da603" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e78f5-a4c1-73aa-b150-0feb2b8f64d4" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_019e78f5-a4c1-709e-b0bb-cf02461da603" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_019e78f5-a4c1-7e30-b0ee-7afbf9b82f16" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019e78f5-a4c1-709e-b0bb-cf02461da603" xlink:to="loc_srt_CounterpartyNameAxis_019e78f5-a4c1-7e30-b0ee-7afbf9b82f16" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e78f5-a4c1-7e30-b0ee-7afbf9b82f16_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_019e78f5-a4c1-7e30-b0ee-7afbf9b82f16" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e78f5-a4c1-7e30-b0ee-7afbf9b82f16_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e78f5-a4c1-7834-bf3d-647417390eb0" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_019e78f5-a4c1-7e30-b0ee-7afbf9b82f16" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e78f5-a4c1-7834-bf3d-647417390eb0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_ProFracHoldingsLLCMember_019e78f5-a4c1-7898-9617-018d5fe3e238" xlink:href="ftk-20260630.xsd#ftk_ProFracHoldingsLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e78f5-a4c1-7834-bf3d-647417390eb0" xlink:to="loc_ftk_ProFracHoldingsLLCMember_019e78f5-a4c1-7898-9617-018d5fe3e238" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightAxis_019e78f5-a4c1-7d28-a9a2-a268a1c46ee0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019e78f5-a4c1-709e-b0bb-cf02461da603" xlink:to="loc_us-gaap_ClassOfWarrantOrRightAxis_019e78f5-a4c1-7d28-a9a2-a268a1c46ee0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_019e78f5-a4c1-7d28-a9a2-a268a1c46ee0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_019e78f5-a4c1-7d28-a9a2-a268a1c46ee0" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_019e78f5-a4c1-7d28-a9a2-a268a1c46ee0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_019e78f5-a4c1-7c1e-8692-168e9cf638c6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_019e78f5-a4c1-7d28-a9a2-a268a1c46ee0" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_019e78f5-a4c1-7c1e-8692-168e9cf638c6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_June2022WarrantsMember_019e78f5-a4c1-7391-b1ed-bb6d41d4329d" xlink:href="ftk-20260630.xsd#ftk_June2022WarrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_019e78f5-a4c1-7c1e-8692-168e9cf638c6" xlink:to="loc_ftk_June2022WarrantsMember_019e78f5-a4c1-7391-b1ed-bb6d41d4329d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a4c1-74d1-a758-d4c0fa02e6a5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019e78f5-a4c1-709e-b0bb-cf02461da603" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a4c1-74d1-a758-d4c0fa02e6a5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-74d1-a758-d4c0fa02e6a5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a4c1-74d1-a758-d4c0fa02e6a5" xlink:to="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-74d1-a758-d4c0fa02e6a5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-7f9d-baaf-ad5decc16f74" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a4c1-74d1-a758-d4c0fa02e6a5" xlink:to="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-7f9d-baaf-ad5decc16f74" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_019e78f5-a4c1-7f97-a643-a500b3f3ab18" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-7f9d-baaf-ad5decc16f74" xlink:to="loc_srt_AffiliatedEntityMember_019e78f5-a4c1-7f97-a643-a500b3f3ab18" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockAndWarrantsIssuedDuringPeriodValuePreferredStockAndWarrants_019e78f5-a4c1-7902-aea8-d3ec0e930821" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockAndWarrantsIssuedDuringPeriodValuePreferredStockAndWarrants"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e78f5-a4c1-73aa-b150-0feb2b8f64d4" xlink:to="loc_us-gaap_StockAndWarrantsIssuedDuringPeriodValuePreferredStockAndWarrants_019e78f5-a4c1-7902-aea8-d3ec0e930821" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_019e78f5-a4c1-74cf-9f24-e40e53a38656" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e78f5-a4c1-73aa-b150-0feb2b8f64d4" xlink:to="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_019e78f5-a4c1-74cf-9f24-e40e53a38656" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_019e78f5-a4c1-7798-af5b-9da5ee36f218" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e78f5-a4c1-73aa-b150-0feb2b8f64d4" xlink:to="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_019e78f5-a4c1-7798-af5b-9da5ee36f218" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_WarrantExerciseFee_019e78f5-a4c1-752d-960f-a9b3088f2783" xlink:href="ftk-20260630.xsd#ftk_WarrantExerciseFee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e78f5-a4c1-73aa-b150-0feb2b8f64d4" xlink:to="loc_ftk_WarrantExerciseFee_019e78f5-a4c1-752d-960f-a9b3088f2783" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_ConditionalProceedsTrigger_019e78f5-a4c1-7569-984e-4208ade94e01" xlink:href="ftk-20260630.xsd#ftk_ConditionalProceedsTrigger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e78f5-a4c1-73aa-b150-0feb2b8f64d4" xlink:to="loc_ftk_ConditionalProceedsTrigger_019e78f5-a4c1-7569-984e-4208ade94e01" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/StockholdersEquityPWRtekTransactionsDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#StockholdersEquityPWRtekTransactionsDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/StockholdersEquityPWRtekTransactionsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_019e78f5-a4c1-72ec-b375-1e278758343e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_019e78f5-a4c1-721b-8422-ac7743f66c8e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e78f5-a4c1-72ec-b375-1e278758343e" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_019e78f5-a4c1-721b-8422-ac7743f66c8e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionAxis_019e78f5-a4c1-7982-9403-2fe91b4a9257" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019e78f5-a4c1-721b-8422-ac7743f66c8e" xlink:to="loc_us-gaap_AssetAcquisitionAxis_019e78f5-a4c1-7982-9403-2fe91b4a9257" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionDomain_019e78f5-a4c1-7982-9403-2fe91b4a9257_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetAcquisitionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AssetAcquisitionAxis_019e78f5-a4c1-7982-9403-2fe91b4a9257" xlink:to="loc_us-gaap_AssetAcquisitionDomain_019e78f5-a4c1-7982-9403-2fe91b4a9257_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionDomain_019e78f5-a4c1-7426-8865-46974960538b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetAcquisitionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AssetAcquisitionAxis_019e78f5-a4c1-7982-9403-2fe91b4a9257" xlink:to="loc_us-gaap_AssetAcquisitionDomain_019e78f5-a4c1-7426-8865-46974960538b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_AcquiredAssetsMember_019e78f5-a4c1-739f-96b0-1718b45b36cf" xlink:href="ftk-20260630.xsd#ftk_AcquiredAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetAcquisitionDomain_019e78f5-a4c1-7426-8865-46974960538b" xlink:to="loc_ftk_AcquiredAssetsMember_019e78f5-a4c1-739f-96b0-1718b45b36cf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightAxis_019e78f5-a4c1-7c0a-96ca-5835f192282e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019e78f5-a4c1-721b-8422-ac7743f66c8e" xlink:to="loc_us-gaap_ClassOfWarrantOrRightAxis_019e78f5-a4c1-7c0a-96ca-5835f192282e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_019e78f5-a4c1-7c0a-96ca-5835f192282e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_019e78f5-a4c1-7c0a-96ca-5835f192282e" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_019e78f5-a4c1-7c0a-96ca-5835f192282e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_019e78f5-a4c1-7c05-ad85-570708bd1a5d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_019e78f5-a4c1-7c0a-96ca-5835f192282e" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_019e78f5-a4c1-7c05-ad85-570708bd1a5d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_April2025WarrantsMember_019e78f5-a4c1-7e07-8d0d-0c82763bf644" xlink:href="ftk-20260630.xsd#ftk_April2025WarrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_019e78f5-a4c1-7c05-ad85-570708bd1a5d" xlink:to="loc_ftk_April2025WarrantsMember_019e78f5-a4c1-7e07-8d0d-0c82763bf644" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_019fac30-f5fc-70fc-9611-0d8dbea010fe" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019e78f5-a4c1-721b-8422-ac7743f66c8e" xlink:to="loc_srt_OwnershipAxis_019fac30-f5fc-70fc-9611-0d8dbea010fe" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_019fac30-f5fc-70fc-9611-0d8dbea010fe_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_019fac30-f5fc-70fc-9611-0d8dbea010fe" xlink:to="loc_srt_OwnershipDomain_019fac30-f5fc-70fc-9611-0d8dbea010fe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_019fac30-f5fc-7336-b620-cf0c311e3791" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_019fac30-f5fc-70fc-9611-0d8dbea010fe" xlink:to="loc_srt_OwnershipDomain_019fac30-f5fc-7336-b620-cf0c311e3791" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_FlotekIndustriesIncMember_019fac31-3580-7693-a134-68b267c18c39" xlink:href="ftk-20260630.xsd#ftk_FlotekIndustriesIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_019fac30-f5fc-7336-b620-cf0c311e3791" xlink:to="loc_ftk_FlotekIndustriesIncMember_019fac31-3580-7693-a134-68b267c18c39" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_019fb3cf-43fa-72ad-b68f-e48af08fa6b6" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019e78f5-a4c1-721b-8422-ac7743f66c8e" xlink:to="loc_dei_LegalEntityAxis_019fb3cf-43fa-72ad-b68f-e48af08fa6b6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019fb3cf-43fa-72ad-b68f-e48af08fa6b6_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_019fb3cf-43fa-72ad-b68f-e48af08fa6b6" xlink:to="loc_dei_EntityDomain_019fb3cf-43fa-72ad-b68f-e48af08fa6b6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019fb3cf-43fa-7a10-9fca-035bdcf9ca50" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_019fb3cf-43fa-72ad-b68f-e48af08fa6b6" xlink:to="loc_dei_EntityDomain_019fb3cf-43fa-7a10-9fca-035bdcf9ca50" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_ProFracHoldingsLLCMember_019fb3cf-7374-735f-88c7-3c1ada51c665" xlink:href="ftk-20260630.xsd#ftk_ProFracHoldingsLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_019fb3cf-43fa-7a10-9fca-035bdcf9ca50" xlink:to="loc_ftk_ProFracHoldingsLLCMember_019fb3cf-7374-735f-88c7-3c1ada51c665" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_019e78f5-a4c1-7571-a235-252d7fa5bb04" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e78f5-a4c1-72ec-b375-1e278758343e" xlink:to="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_019e78f5-a4c1-7571-a235-252d7fa5bb04" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WarrantsAndRightsOutstandingTerm_019e78f5-a4c1-7ecb-9f1c-4895b343fef7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WarrantsAndRightsOutstandingTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e78f5-a4c1-72ec-b375-1e278758343e" xlink:to="loc_us-gaap_WarrantsAndRightsOutstandingTerm_019e78f5-a4c1-7ecb-9f1c-4895b343fef7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_019e78f5-a4c1-7f85-a9c9-d8146aebb25b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e78f5-a4c1-72ec-b375-1e278758343e" xlink:to="loc_us-gaap_CommonStockSharesIssued_019e78f5-a4c1-7f85-a9c9-d8146aebb25b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_019fac30-4c31-711f-9839-c3fbd7852d1b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MinorityInterestOwnershipPercentageByParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e78f5-a4c1-72ec-b375-1e278758343e" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_019fac30-4c31-711f-9839-c3fbd7852d1b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_ClassOfWarrantOrRightIssuanceCost_019fac56-82ef-7e58-9317-d4b3be2f7ee6" xlink:href="ftk-20260630.xsd#ftk_ClassOfWarrantOrRightIssuanceCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e78f5-a4c1-72ec-b375-1e278758343e" xlink:to="loc_ftk_ClassOfWarrantOrRightIssuanceCost_019fac56-82ef-7e58-9317-d4b3be2f7ee6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_AssetAcquisitionEstimatedBookValue_019fa3fd-7204-79a2-9c87-bddb6145d522" xlink:href="ftk-20260630.xsd#ftk_AssetAcquisitionEstimatedBookValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e78f5-a4c1-72ec-b375-1e278758343e" xlink:to="loc_ftk_AssetAcquisitionEstimatedBookValue_019fa3fd-7204-79a2-9c87-bddb6145d522" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_AssetAcquisitionExcessConsiderationOfAssetBookValue_019fa3fd-7204-7172-a1a3-6df01682329b" xlink:href="ftk-20260630.xsd#ftk_AssetAcquisitionExcessConsiderationOfAssetBookValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e78f5-a4c1-72ec-b375-1e278758343e" xlink:to="loc_ftk_AssetAcquisitionExcessConsiderationOfAssetBookValue_019fa3fd-7204-7172-a1a3-6df01682329b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WarrantsAndRightsOutstanding_019fac57-7db0-780c-971b-8360d87fcad9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WarrantsAndRightsOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e78f5-a4c1-72ec-b375-1e278758343e" xlink:to="loc_us-gaap_WarrantsAndRightsOutstanding_019fac57-7db0-780c-971b-8360d87fcad9" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/StockholdersEquityTreasuryStockDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#StockholdersEquityTreasuryStockDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/StockholdersEquityTreasuryStockDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityClassOfTreasuryStockLineItems_019e78f5-a4c1-75a1-ab1e-95c0fa1a4960" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityClassOfTreasuryStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfTreasuryStockTable_019e78f5-a4c1-7a82-8561-b2c93421d756" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfTreasuryStockTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_019e78f5-a4c1-75a1-ab1e-95c0fa1a4960" xlink:to="loc_us-gaap_ClassOfTreasuryStockTable_019e78f5-a4c1-7a82-8561-b2c93421d756" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019e78f5-a4c1-723f-a932-e1cf8b7644fb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ClassOfTreasuryStockTable_019e78f5-a4c1-7a82-8561-b2c93421d756" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019e78f5-a4c1-723f-a932-e1cf8b7644fb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e78f5-a4c1-723f-a932-e1cf8b7644fb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e78f5-a4c1-723f-a932-e1cf8b7644fb" xlink:to="loc_us-gaap_EquityComponentDomain_019e78f5-a4c1-723f-a932-e1cf8b7644fb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e78f5-a4c1-71f7-914b-467ffb8b75a2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e78f5-a4c1-723f-a932-e1cf8b7644fb" xlink:to="loc_us-gaap_EquityComponentDomain_019e78f5-a4c1-71f7-914b-467ffb8b75a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonMember_019e78f5-a4c1-73a0-adad-c4334d05ef67" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockCommonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e78f5-a4c1-71f7-914b-467ffb8b75a2" xlink:to="loc_us-gaap_TreasuryStockCommonMember_019e78f5-a4c1-73a0-adad-c4334d05ef67" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_019e78f5-a4c1-7343-8210-f6bd08e649c3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_019e78f5-a4c1-75a1-ab1e-95c0fa1a4960" xlink:to="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_019e78f5-a4c1-7343-8210-f6bd08e649c3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardForfeited_019e78f5-a4c1-7a82-972b-7abd371cbb4c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardForfeited"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_019e78f5-a4c1-75a1-ab1e-95c0fa1a4960" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardForfeited_019e78f5-a4c1-7a82-972b-7abd371cbb4c" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/SupplementalCashFlowInformationDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#SupplementalCashFlowInformationDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/SupplementalCashFlowInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_019f89b4-5a32-7be7-ac23-749a1c8a1435" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019f89b4-5a32-7877-b751-91ef8d848073" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019f89b4-5a32-7be7-ac23-749a1c8a1435" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019f89b4-5a32-7877-b751-91ef8d848073" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019f89b4-5a32-7b69-aaca-e71bd151add4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019f89b4-5a32-7877-b751-91ef8d848073" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019f89b4-5a32-7b69-aaca-e71bd151add4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019f89b4-5a32-7b69-aaca-e71bd151add4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019f89b4-5a32-7b69-aaca-e71bd151add4" xlink:to="loc_us-gaap_RelatedPartyDomain_019f89b4-5a32-7b69-aaca-e71bd151add4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019f89b4-5a32-7d06-ab17-2c5b0d610b35" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019f89b4-5a32-7b69-aaca-e71bd151add4" xlink:to="loc_us-gaap_RelatedPartyDomain_019f89b4-5a32-7d06-ab17-2c5b0d610b35" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019f89b4-5a32-7c41-9d4b-a9df539f3cba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019f89b4-5a32-7d06-ab17-2c5b0d610b35" xlink:to="loc_us-gaap_RelatedPartyMember_019f89b4-5a32-7c41-9d4b-a9df539f3cba" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_ContractShortfallFeeOffset_019f89b4-5a32-7958-ae0c-e4b0496079a4" xlink:href="ftk-20260630.xsd#ftk_ContractShortfallFeeOffset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019f89b4-5a32-7be7-ac23-749a1c8a1435" xlink:to="loc_ftk_ContractShortfallFeeOffset_019f89b4-5a32-7958-ae0c-e4b0496079a4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_019f89b4-5a32-770a-97d8-9f82858a17b2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019f89b4-5a32-7be7-ac23-749a1c8a1435" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_019f89b4-5a32-770a-97d8-9f82858a17b2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_AssetAcquisitionPartsInventory_019f89b4-5a32-752b-ae2e-ac474b5a6e0d" xlink:href="ftk-20260630.xsd#ftk_AssetAcquisitionPartsInventory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019f89b4-5a32-7be7-ac23-749a1c8a1435" xlink:to="loc_ftk_AssetAcquisitionPartsInventory_019f89b4-5a32-752b-ae2e-ac474b5a6e0d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_AssetAcquisitionEquipmentInventory_019f89b4-5a32-7bd2-8c4e-1920a7b590ed" xlink:href="ftk-20260630.xsd#ftk_AssetAcquisitionEquipmentInventory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019f89b4-5a32-7be7-ac23-749a1c8a1435" xlink:to="loc_ftk_AssetAcquisitionEquipmentInventory_019f89b4-5a32-7bd2-8c4e-1920a7b590ed" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_AssetAcquisitionRecognizedLiabilityAssumedFinancialLiability_019f89b4-5a32-7171-bf50-d3bcb4aa3df2" xlink:href="ftk-20260630.xsd#ftk_AssetAcquisitionRecognizedLiabilityAssumedFinancialLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019f89b4-5a32-7be7-ac23-749a1c8a1435" xlink:to="loc_ftk_AssetAcquisitionRecognizedLiabilityAssumedFinancialLiability_019f89b4-5a32-7171-bf50-d3bcb4aa3df2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_AssetAcquisitionExcessConsiderationOfAssetBookValue_019f89b4-5a32-7eb6-ac8d-9de4b8bda920" xlink:href="ftk-20260630.xsd#ftk_AssetAcquisitionExcessConsiderationOfAssetBookValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019f89b4-5a32-7be7-ac23-749a1c8a1435" xlink:to="loc_ftk_AssetAcquisitionExcessConsiderationOfAssetBookValue_019f89b4-5a32-7eb6-ac8d-9de4b8bda920" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_AssetAcquisitionWarrantsIssuedConvertibleSharesValue_019f89b4-5a32-7cbb-beb6-1bd47fde4f09" xlink:href="ftk-20260630.xsd#ftk_AssetAcquisitionWarrantsIssuedConvertibleSharesValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019f89b4-5a32-7be7-ac23-749a1c8a1435" xlink:to="loc_ftk_AssetAcquisitionWarrantsIssuedConvertibleSharesValue_019f89b4-5a32-7cbb-beb6-1bd47fde4f09" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPaidNet_019e78f5-a4c1-7af2-b82c-e4b69028fbd3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestPaidNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019f89b4-5a32-7be7-ac23-749a1c8a1435" xlink:to="loc_us-gaap_InterestPaidNet_019e78f5-a4c1-7af2-b82c-e4b69028fbd3" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxesPaidNet_019fcb21-1397-7c5d-af66-728f43f739ec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxesPaidNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019f89b4-5a32-7be7-ac23-749a1c8a1435" xlink:to="loc_us-gaap_IncomeTaxesPaidNet_019fcb21-1397-7c5d-af66-728f43f739ec" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_NonCashEquipmentCredit_019e78f5-a4c1-7d3c-b535-cdaa70d51113" xlink:href="ftk-20260630.xsd#ftk_NonCashEquipmentCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019f89b4-5a32-7be7-ac23-749a1c8a1435" xlink:to="loc_ftk_NonCashEquipmentCredit_019e78f5-a4c1-7d3c-b535-cdaa70d51113" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_EquipmentPurchasesOffsetOfReceivables_019e78f5-a4c1-76fb-85b6-7b3f1471b8bc" xlink:href="ftk-20260630.xsd#ftk_EquipmentPurchasesOffsetOfReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019f89b4-5a32-7be7-ac23-749a1c8a1435" xlink:to="loc_ftk_EquipmentPurchasesOffsetOfReceivables_019e78f5-a4c1-76fb-85b6-7b3f1471b8bc" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1_019f89b7-be40-7ee2-8399-90e13a8eed27" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019f89b4-5a32-7be7-ac23-749a1c8a1435" xlink:to="loc_us-gaap_NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1_019f89b7-be40-7ee2-8399-90e13a8eed27" xlink:type="arc" order="11"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/RelatedPartyTransactionsDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#RelatedPartyTransactionsDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/RelatedPartyTransactionsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_019e78f5-a4c1-7a54-bc04-c8b23c69785f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e78f5-a4c1-76b4-87e6-6fe8aa6c4519" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e78f5-a4c1-7a54-bc04-c8b23c69785f" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e78f5-a4c1-76b4-87e6-6fe8aa6c4519" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_019e78f5-a4c1-78f3-9daa-6ad76869e596" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e78f5-a4c1-76b4-87e6-6fe8aa6c4519" xlink:to="loc_srt_CounterpartyNameAxis_019e78f5-a4c1-78f3-9daa-6ad76869e596" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e78f5-a4c1-78f3-9daa-6ad76869e596_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_019e78f5-a4c1-78f3-9daa-6ad76869e596" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e78f5-a4c1-78f3-9daa-6ad76869e596_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e78f5-a4c1-7896-af64-50f670a394ae" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_019e78f5-a4c1-78f3-9daa-6ad76869e596" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e78f5-a4c1-7896-af64-50f670a394ae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_PIPETransactionMember_019e78f5-a4c1-725f-9900-5cba6e36d99c" xlink:href="ftk-20260630.xsd#ftk_PIPETransactionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e78f5-a4c1-7896-af64-50f670a394ae" xlink:to="loc_ftk_PIPETransactionMember_019e78f5-a4c1-725f-9900-5cba6e36d99c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_AmendedProFracAgreementMember_019e78f5-a4c1-73cf-b60e-311846e5bef2" xlink:href="ftk-20260630.xsd#ftk_AmendedProFracAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e78f5-a4c1-7896-af64-50f670a394ae" xlink:to="loc_ftk_AmendedProFracAgreementMember_019e78f5-a4c1-73cf-b60e-311846e5bef2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_ProFracHoldingsLLCMember_019e78f5-a4c1-7cb9-bf03-46c3a0cf3f08" xlink:href="ftk-20260630.xsd#ftk_ProFracHoldingsLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019e78f5-a4c1-7896-af64-50f670a394ae" xlink:to="loc_ftk_ProFracHoldingsLLCMember_019e78f5-a4c1-7cb9-bf03-46c3a0cf3f08" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_AdditionalLeasesAxis_019fcff2-169e-753c-9926-51208a156644" xlink:href="ftk-20260630.xsd#ftk_AdditionalLeasesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e78f5-a4c1-76b4-87e6-6fe8aa6c4519" xlink:to="loc_ftk_AdditionalLeasesAxis_019fcff2-169e-753c-9926-51208a156644" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_AdditionalLeasesDomain_019fcff2-169e-753c-9926-51208a156644_default" xlink:href="ftk-20260630.xsd#ftk_AdditionalLeasesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ftk_AdditionalLeasesAxis_019fcff2-169e-753c-9926-51208a156644" xlink:to="loc_ftk_AdditionalLeasesDomain_019fcff2-169e-753c-9926-51208a156644_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_AdditionalLeasesDomain_019fcff1-4e5d-7b9f-8631-c145a5a77f8c" xlink:href="ftk-20260630.xsd#ftk_AdditionalLeasesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ftk_AdditionalLeasesAxis_019fcff2-169e-753c-9926-51208a156644" xlink:to="loc_ftk_AdditionalLeasesDomain_019fcff1-4e5d-7b9f-8631-c145a5a77f8c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_AdditionalLeasedEquipmentMember_019fcff1-8c01-7917-a4bc-23a47aa2fd1e" xlink:href="ftk-20260630.xsd#ftk_AdditionalLeasedEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ftk_AdditionalLeasesDomain_019fcff1-4e5d-7b9f-8631-c145a5a77f8c" xlink:to="loc_ftk_AdditionalLeasedEquipmentMember_019fcff1-8c01-7917-a4bc-23a47aa2fd1e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e78f5-a4c1-77ce-a7c4-f6a6e2c96c0b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e78f5-a4c1-76b4-87e6-6fe8aa6c4519" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e78f5-a4c1-77ce-a7c4-f6a6e2c96c0b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e78f5-a4c1-77ce-a7c4-f6a6e2c96c0b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e78f5-a4c1-77ce-a7c4-f6a6e2c96c0b" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e78f5-a4c1-77ce-a7c4-f6a6e2c96c0b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e78f5-a4c1-7e99-b7f4-2d55c7d93f4a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e78f5-a4c1-77ce-a7c4-f6a6e2c96c0b" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e78f5-a4c1-7e99-b7f4-2d55c7d93f4a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_019e78f5-a4c1-75cd-aa0c-60e28a7b8def" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e78f5-a4c1-7e99-b7f4-2d55c7d93f4a" xlink:to="loc_us-gaap_ConvertibleDebtMember_019e78f5-a4c1-75cd-aa0c-60e28a7b8def" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a4c1-7fdf-93cc-93a997f6b612" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e78f5-a4c1-76b4-87e6-6fe8aa6c4519" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a4c1-7fdf-93cc-93a997f6b612" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-7fdf-93cc-93a997f6b612_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a4c1-7fdf-93cc-93a997f6b612" xlink:to="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-7fdf-93cc-93a997f6b612_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-792b-b6a3-d64944b7f879" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a4c1-7fdf-93cc-93a997f6b612" xlink:to="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-792b-b6a3-d64944b7f879" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019e78f5-a4c1-74a0-b053-a49f62108a27" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-792b-b6a3-d64944b7f879" xlink:to="loc_us-gaap_RelatedPartyMember_019e78f5-a4c1-74a0-b053-a49f62108a27" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_019e78f5-a4c1-77c4-9904-e2d23c99aef4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e78f5-a4c1-76b4-87e6-6fe8aa6c4519" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_019e78f5-a4c1-77c4-9904-e2d23c99aef4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_019e78f5-a4c1-77c4-9904-e2d23c99aef4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_019e78f5-a4c1-77c4-9904-e2d23c99aef4" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_019e78f5-a4c1-77c4-9904-e2d23c99aef4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_019e78f5-a4c1-7ad8-aada-e120626a0f1e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_019e78f5-a4c1-77c4-9904-e2d23c99aef4" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_019e78f5-a4c1-7ad8-aada-e120626a0f1e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_ContractShortfallFeesMember_019e78f5-a4c1-789c-b87e-e36cb4f4b3c6" xlink:href="ftk-20260630.xsd#ftk_ContractShortfallFeesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_019e78f5-a4c1-7ad8-aada-e120626a0f1e" xlink:to="loc_ftk_ContractShortfallFeesMember_019e78f5-a4c1-789c-b87e-e36cb4f4b3c6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_ProFracHoldingsLLCMember_019e78f5-a4c1-75af-af25-9a2ffea48dcf" xlink:href="ftk-20260630.xsd#ftk_ProFracHoldingsLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_019e78f5-a4c1-7ad8-aada-e120626a0f1e" xlink:to="loc_ftk_ProFracHoldingsLLCMember_019e78f5-a4c1-75af-af25-9a2ffea48dcf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019e78f5-a4c1-7b5e-81f4-7b325d696b9d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e78f5-a4c1-76b4-87e6-6fe8aa6c4519" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019e78f5-a4c1-7b5e-81f4-7b325d696b9d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_019e78f5-a4c1-7b5e-81f4-7b325d696b9d_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019e78f5-a4c1-7b5e-81f4-7b325d696b9d" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_019e78f5-a4c1-7b5e-81f4-7b325d696b9d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_019e78f5-a4c1-7f6b-936c-cecb4a4eedc2" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019e78f5-a4c1-7b5e-81f4-7b325d696b9d" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_019e78f5-a4c1-7f6b-936c-cecb4a4eedc2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_ProFracHoldingsLLCMember_019e78f5-a4c1-74ee-add6-c1603ab79164" xlink:href="ftk-20260630.xsd#ftk_ProFracHoldingsLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_019e78f5-a4c1-7f6b-936c-cecb4a4eedc2" xlink:to="loc_ftk_ProFracHoldingsLLCMember_019e78f5-a4c1-74ee-add6-c1603ab79164" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionAxis_019e78f5-a4c1-7fbe-80e4-b1047c36c2b8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e78f5-a4c1-76b4-87e6-6fe8aa6c4519" xlink:to="loc_us-gaap_AssetAcquisitionAxis_019e78f5-a4c1-7fbe-80e4-b1047c36c2b8" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionDomain_019e78f5-a4c1-7fbe-80e4-b1047c36c2b8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetAcquisitionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AssetAcquisitionAxis_019e78f5-a4c1-7fbe-80e4-b1047c36c2b8" xlink:to="loc_us-gaap_AssetAcquisitionDomain_019e78f5-a4c1-7fbe-80e4-b1047c36c2b8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionDomain_019e78f5-a4c1-7d43-835e-10e07d1c7f56" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetAcquisitionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AssetAcquisitionAxis_019e78f5-a4c1-7fbe-80e4-b1047c36c2b8" xlink:to="loc_us-gaap_AssetAcquisitionDomain_019e78f5-a4c1-7d43-835e-10e07d1c7f56" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_AcquiredAssetsMember_019e78f5-a4c1-7820-be19-2b75431dd7be" xlink:href="ftk-20260630.xsd#ftk_AcquiredAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetAcquisitionDomain_019e78f5-a4c1-7d43-835e-10e07d1c7f56" xlink:to="loc_ftk_AcquiredAssetsMember_019e78f5-a4c1-7820-be19-2b75431dd7be" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightAxis_019e78f5-a4c1-7db8-b326-51b9e7053a8a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e78f5-a4c1-76b4-87e6-6fe8aa6c4519" xlink:to="loc_us-gaap_ClassOfWarrantOrRightAxis_019e78f5-a4c1-7db8-b326-51b9e7053a8a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_019e78f5-a4c1-7db8-b326-51b9e7053a8a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_019e78f5-a4c1-7db8-b326-51b9e7053a8a" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_019e78f5-a4c1-7db8-b326-51b9e7053a8a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_019e78f5-a4c1-7071-9419-4b99be62f1f1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_019e78f5-a4c1-7db8-b326-51b9e7053a8a" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_019e78f5-a4c1-7071-9419-4b99be62f1f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_April2025WarrantsMember_019e78f5-a4c1-7426-a8a3-7d5aaef358db" xlink:href="ftk-20260630.xsd#ftk_April2025WarrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_019e78f5-a4c1-7071-9419-4b99be62f1f1" xlink:to="loc_ftk_April2025WarrantsMember_019e78f5-a4c1-7426-a8a3-7d5aaef358db" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_SettlementInstrumentAxis_019e78f5-a4c1-7709-9f8a-10c3edc4a536" xlink:href="ftk-20260630.xsd#ftk_SettlementInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e78f5-a4c1-76b4-87e6-6fe8aa6c4519" xlink:to="loc_ftk_SettlementInstrumentAxis_019e78f5-a4c1-7709-9f8a-10c3edc4a536" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_SettlementInstrumentDomain_019e78f5-a4c1-7709-9f8a-10c3edc4a536_default" xlink:href="ftk-20260630.xsd#ftk_SettlementInstrumentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ftk_SettlementInstrumentAxis_019e78f5-a4c1-7709-9f8a-10c3edc4a536" xlink:to="loc_ftk_SettlementInstrumentDomain_019e78f5-a4c1-7709-9f8a-10c3edc4a536_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_SettlementInstrumentDomain_019e78f5-a4c1-74d7-bd7f-9f2739c5cedb" xlink:href="ftk-20260630.xsd#ftk_SettlementInstrumentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ftk_SettlementInstrumentAxis_019e78f5-a4c1-7709-9f8a-10c3edc4a536" xlink:to="loc_ftk_SettlementInstrumentDomain_019e78f5-a4c1-74d7-bd7f-9f2739c5cedb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_SettlementInstrumentCashMember_019e78f5-a4c1-7bd1-a841-d0466fcd55c5" xlink:href="ftk-20260630.xsd#ftk_SettlementInstrumentCashMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ftk_SettlementInstrumentDomain_019e78f5-a4c1-74d7-bd7f-9f2739c5cedb" xlink:to="loc_ftk_SettlementInstrumentCashMember_019e78f5-a4c1-7bd1-a841-d0466fcd55c5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_SettlementInstrumentEquipmentCreditMember_019e78f5-a4c1-7b70-a595-fee21bb191e0" xlink:href="ftk-20260630.xsd#ftk_SettlementInstrumentEquipmentCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ftk_SettlementInstrumentDomain_019e78f5-a4c1-74d7-bd7f-9f2739c5cedb" xlink:to="loc_ftk_SettlementInstrumentEquipmentCreditMember_019e78f5-a4c1-7b70-a595-fee21bb191e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_019e78f5-a4c1-71b3-a27e-179c059427f1" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e78f5-a4c1-76b4-87e6-6fe8aa6c4519" xlink:to="loc_srt_MajorCustomersAxis_019e78f5-a4c1-71b3-a27e-179c059427f1" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_019e78f5-a4c1-71b3-a27e-179c059427f1_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_019e78f5-a4c1-71b3-a27e-179c059427f1" xlink:to="loc_srt_NameOfMajorCustomerDomain_019e78f5-a4c1-71b3-a27e-179c059427f1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_019e78f5-a4c1-74e8-9bbb-32d4f921edbf" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_019e78f5-a4c1-71b3-a27e-179c059427f1" xlink:to="loc_srt_NameOfMajorCustomerDomain_019e78f5-a4c1-74e8-9bbb-32d4f921edbf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_ProFracAgreementMember_019e78f5-a4c1-76d4-9883-6be3e295edf8" xlink:href="ftk-20260630.xsd#ftk_ProFracAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_019e78f5-a4c1-74e8-9bbb-32d4f921edbf" xlink:to="loc_ftk_ProFracAgreementMember_019e78f5-a4c1-76d4-9883-6be3e295edf8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_LeaseArrangementAxis_019e78f5-a4c1-7b9a-9496-ba4e09b261be" xlink:href="ftk-20260630.xsd#ftk_LeaseArrangementAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e78f5-a4c1-76b4-87e6-6fe8aa6c4519" xlink:to="loc_ftk_LeaseArrangementAxis_019e78f5-a4c1-7b9a-9496-ba4e09b261be" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_LeaseArrangementDomain_019e78f5-a4c1-7b9a-9496-ba4e09b261be_default" xlink:href="ftk-20260630.xsd#ftk_LeaseArrangementDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ftk_LeaseArrangementAxis_019e78f5-a4c1-7b9a-9496-ba4e09b261be" xlink:to="loc_ftk_LeaseArrangementDomain_019e78f5-a4c1-7b9a-9496-ba4e09b261be_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_LeaseArrangementDomain_019e78f5-a4c1-7d01-8cd5-69ed637bda75" xlink:href="ftk-20260630.xsd#ftk_LeaseArrangementDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ftk_LeaseArrangementAxis_019e78f5-a4c1-7b9a-9496-ba4e09b261be" xlink:to="loc_ftk_LeaseArrangementDomain_019e78f5-a4c1-7d01-8cd5-69ed637bda75" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_PWRTEKLLCMember_019e78f5-a4c1-7cc0-a81e-e47d8de5c52c" xlink:href="ftk-20260630.xsd#ftk_PWRTEKLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ftk_LeaseArrangementDomain_019e78f5-a4c1-7d01-8cd5-69ed637bda75" xlink:to="loc_ftk_PWRTEKLLCMember_019e78f5-a4c1-7cc0-a81e-e47d8de5c52c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_LeasedEquipmentMember_019fd26c-f1ab-7c98-b682-fa5a479caa21" xlink:href="ftk-20260630.xsd#ftk_LeasedEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ftk_LeaseArrangementDomain_019e78f5-a4c1-7d01-8cd5-69ed637bda75" xlink:to="loc_ftk_LeasedEquipmentMember_019fd26c-f1ab-7c98-b682-fa5a479caa21" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_019e78f5-a4c1-7729-bc89-4bb30402eadb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e78f5-a4c1-7a54-bc04-c8b23c69785f" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_019e78f5-a4c1-7729-bc89-4bb30402eadb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_AssetPurchaseCommitmentPercentageOfFleet_019e78f5-a4c1-72e7-abdb-90ffede9f774" xlink:href="ftk-20260630.xsd#ftk_AssetPurchaseCommitmentPercentageOfFleet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e78f5-a4c1-7a54-bc04-c8b23c69785f" xlink:to="loc_ftk_AssetPurchaseCommitmentPercentageOfFleet_019e78f5-a4c1-72e7-abdb-90ffede9f774" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_ConditionalRevenueShortfallRateIfChemicalRequirementRateIsUnmet_019e78f5-a4c1-7f79-9ff6-3fb898df1eda" xlink:href="ftk-20260630.xsd#ftk_ConditionalRevenueShortfallRateIfChemicalRequirementRateIsUnmet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e78f5-a4c1-7a54-bc04-c8b23c69785f" xlink:to="loc_ftk_ConditionalRevenueShortfallRateIfChemicalRequirementRateIsUnmet_019e78f5-a4c1-7f79-9ff6-3fb898df1eda" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_MinimumFleetPurchaseRequirement_019e78f5-a4c1-7f9c-9445-e8710b8c3495" xlink:href="ftk-20260630.xsd#ftk_MinimumFleetPurchaseRequirement"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e78f5-a4c1-7a54-bc04-c8b23c69785f" xlink:to="loc_ftk_MinimumFleetPurchaseRequirement_019e78f5-a4c1-7f9c-9445-e8710b8c3495" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_PotentialIncreaseToContractTerm_019e78f5-a4c1-78f1-be9c-dda409c223ff" xlink:href="ftk-20260630.xsd#ftk_PotentialIncreaseToContractTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e78f5-a4c1-7a54-bc04-c8b23c69785f" xlink:to="loc_ftk_PotentialIncreaseToContractTerm_019e78f5-a4c1-78f1-be9c-dda409c223ff" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionConsiderationTransferred_019e78f5-a4c1-7b00-9988-83690d9f695b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetAcquisitionConsiderationTransferred"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e78f5-a4c1-7a54-bc04-c8b23c69785f" xlink:to="loc_us-gaap_AssetAcquisitionConsiderationTransferred_019e78f5-a4c1-7b00-9988-83690d9f695b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseTermOfContract_019e78f5-a4c1-7ad4-b583-60e607d54960" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseTermOfContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e78f5-a4c1-7a54-bc04-c8b23c69785f" xlink:to="loc_us-gaap_LesseeOperatingLeaseTermOfContract_019e78f5-a4c1-7ad4-b583-60e607d54960" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_NumberOfOperatingMobilePowerGenerationAssets_019fcbbf-bd6c-7a98-9d52-3f1f17488cb1" xlink:href="ftk-20260630.xsd#ftk_NumberOfOperatingMobilePowerGenerationAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e78f5-a4c1-7a54-bc04-c8b23c69785f" xlink:to="loc_ftk_NumberOfOperatingMobilePowerGenerationAssets_019fcbbf-bd6c-7a98-9d52-3f1f17488cb1" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction_019e78f5-a4c1-7d29-a9d6-a497f5e39662" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionAmountsOfTransaction"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e78f5-a4c1-7a54-bc04-c8b23c69785f" xlink:to="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction_019e78f5-a4c1-7d29-a9d6-a497f5e39662" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleAndCollectionOfReceivables_019e78f5-a4c1-7f75-a07c-69bc1de5c61e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromSaleAndCollectionOfReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e78f5-a4c1-7a54-bc04-c8b23c69785f" xlink:to="loc_us-gaap_ProceedsFromSaleAndCollectionOfReceivables_019e78f5-a4c1-7f75-a07c-69bc1de5c61e" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_IncreaseDecreaseInEquipmentCredit_019e78f5-a4c1-7073-a626-b89540c2257b" xlink:href="ftk-20260630.xsd#ftk_IncreaseDecreaseInEquipmentCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e78f5-a4c1-7a54-bc04-c8b23c69785f" xlink:to="loc_ftk_IncreaseDecreaseInEquipmentCredit_019e78f5-a4c1-7073-a626-b89540c2257b" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e78f5-a4c1-7ec1-a9aa-0c5c3be968de" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e78f5-a4c1-7a54-bc04-c8b23c69785f" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e78f5-a4c1-7ec1-a9aa-0c5c3be968de" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostAmortization_019e78f5-a4c1-7a9d-b0e6-783b8efcec79" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizedContractCostAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e78f5-a4c1-7a54-bc04-c8b23c69785f" xlink:to="loc_us-gaap_CapitalizedContractCostAmortization_019e78f5-a4c1-7a9d-b0e6-783b8efcec79" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_019e78f5-a4c1-75b1-b214-66e8681cc7cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e78f5-a4c1-7a54-bc04-c8b23c69785f" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_019e78f5-a4c1-75b1-b214-66e8681cc7cb" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_019e78f5-a4c1-7406-9381-5948d1f979d1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e78f5-a4c1-7a54-bc04-c8b23c69785f" xlink:to="loc_us-gaap_AccountsPayableCurrent_019e78f5-a4c1-7406-9381-5948d1f979d1" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_019e78f5-a4c1-7cd9-a0b3-0f0a4621a3c7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e78f5-a4c1-7a54-bc04-c8b23c69785f" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_019e78f5-a4c1-7cd9-a0b3-0f0a4621a3c7" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_019e78f5-a4c1-764c-a32e-c8a17950c5e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e78f5-a4c1-7a54-bc04-c8b23c69785f" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_019e78f5-a4c1-764c-a32e-c8a17950c5e1" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_019e78f5-a4c1-755e-b015-ae281cbdd832" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e78f5-a4c1-7a54-bc04-c8b23c69785f" xlink:to="loc_us-gaap_CommonStockSharesIssued_019e78f5-a4c1-755e-b015-ae281cbdd832" xlink:type="arc" order="17"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/BusinessSegmentGeographicandMajorCustomerInformationNarrativeDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#BusinessSegmentGeographicandMajorCustomerInformationNarrativeDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/BusinessSegmentGeographicandMajorCustomerInformationNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7c03-bd02-3df3b2768411" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-73b2-8097-2c14fad94c52" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7c03-bd02-3df3b2768411" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-73b2-8097-2c14fad94c52" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_019e78f5-a4c1-7d99-ab16-388e07685c2d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-73b2-8097-2c14fad94c52" xlink:to="loc_srt_ConsolidationItemsAxis_019e78f5-a4c1-7d99-ab16-388e07685c2d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-7d99-ab16-388e07685c2d_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_019e78f5-a4c1-7d99-ab16-388e07685c2d" xlink:to="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-7d99-ab16-388e07685c2d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-7425-82f9-69d9addf304c" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_019e78f5-a4c1-7d99-ab16-388e07685c2d" xlink:to="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-7425-82f9-69d9addf304c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_019e78f5-a4c1-75bf-87ae-021eb4a8d290" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-7425-82f9-69d9addf304c" xlink:to="loc_us-gaap_OperatingSegmentsMember_019e78f5-a4c1-75bf-87ae-021eb4a8d290" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019e78f5-a4c1-72ce-9135-49e51a9ec338" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-73b2-8097-2c14fad94c52" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019e78f5-a4c1-72ce-9135-49e51a9ec338" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e78f5-a4c1-72ce-9135-49e51a9ec338_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e78f5-a4c1-72ce-9135-49e51a9ec338" xlink:to="loc_us-gaap_SegmentDomain_019e78f5-a4c1-72ce-9135-49e51a9ec338_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e78f5-a4c1-7d1f-94c2-3fb9c38df65d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e78f5-a4c1-72ce-9135-49e51a9ec338" xlink:to="loc_us-gaap_SegmentDomain_019e78f5-a4c1-7d1f-94c2-3fb9c38df65d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_ChemistryTechnologiesSegmentMember_019e78f5-a4c1-7ab5-9029-681bf8722881" xlink:href="ftk-20260630.xsd#ftk_ChemistryTechnologiesSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e78f5-a4c1-7d1f-94c2-3fb9c38df65d" xlink:to="loc_ftk_ChemistryTechnologiesSegmentMember_019e78f5-a4c1-7ab5-9029-681bf8722881" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_DataAnalyticsSegmentMember_019e78f5-a4c1-778c-aaa7-128e3b1c3506" xlink:href="ftk-20260630.xsd#ftk_DataAnalyticsSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e78f5-a4c1-7d1f-94c2-3fb9c38df65d" xlink:to="loc_ftk_DataAnalyticsSegmentMember_019e78f5-a4c1-778c-aaa7-128e3b1c3506" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments_019e78f5-a4c1-7e11-a11c-a30911f5e0c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NumberOfReportableSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7c03-bd02-3df3b2768411" xlink:to="loc_us-gaap_NumberOfReportableSegments_019e78f5-a4c1-7e11-a11c-a30911f5e0c1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_019e78f5-a4c1-7c73-9639-84b0c22ab56c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Depreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7c03-bd02-3df3b2768411" xlink:to="loc_us-gaap_Depreciation_019e78f5-a4c1-7c73-9639-84b0c22ab56c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_019e78f5-a4c1-7d7b-9d33-2a107049d5c5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7c03-bd02-3df3b2768411" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_019e78f5-a4c1-7d7b-9d33-2a107049d5c5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_019e78f5-a4c1-778f-b1d6-15ce05dcb128" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnSaleOfPropertyPlantEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7c03-bd02-3df3b2768411" xlink:to="loc_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_019e78f5-a4c1-778f-b1d6-15ce05dcb128" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/BusinessSegmentGeographicandMajorCustomerInformationReportableSegmentsDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#BusinessSegmentGeographicandMajorCustomerInformationReportableSegmentsDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/BusinessSegmentGeographicandMajorCustomerInformationReportableSegmentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7efd-9ea0-13af719411ac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7056-b8d1-3df316d12ad4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7efd-9ea0-13af719411ac" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7056-b8d1-3df316d12ad4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_019e78f5-a4c1-7d3f-b71d-b7fcabb47266" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7056-b8d1-3df316d12ad4" xlink:to="loc_srt_ConsolidationItemsAxis_019e78f5-a4c1-7d3f-b71d-b7fcabb47266" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-7d3f-b71d-b7fcabb47266_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_019e78f5-a4c1-7d3f-b71d-b7fcabb47266" xlink:to="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-7d3f-b71d-b7fcabb47266_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-7dc0-9332-4efa4e2b1466" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_019e78f5-a4c1-7d3f-b71d-b7fcabb47266" xlink:to="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-7dc0-9332-4efa4e2b1466" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_019e78f5-a4c1-78c8-9ea0-d2f17b71a274" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-7dc0-9332-4efa4e2b1466" xlink:to="loc_us-gaap_OperatingSegmentsMember_019e78f5-a4c1-78c8-9ea0-d2f17b71a274" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_019e78f5-a4c1-7a3e-a094-882c8becff73" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-7dc0-9332-4efa4e2b1466" xlink:to="loc_us-gaap_CorporateNonSegmentMember_019e78f5-a4c1-7a3e-a094-882c8becff73" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019e78f5-a4c1-7bea-ae96-0119988d90ee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7056-b8d1-3df316d12ad4" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019e78f5-a4c1-7bea-ae96-0119988d90ee" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e78f5-a4c1-7bea-ae96-0119988d90ee_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e78f5-a4c1-7bea-ae96-0119988d90ee" xlink:to="loc_us-gaap_SegmentDomain_019e78f5-a4c1-7bea-ae96-0119988d90ee_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e78f5-a4c1-7ae9-9483-c374839aa2f4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e78f5-a4c1-7bea-ae96-0119988d90ee" xlink:to="loc_us-gaap_SegmentDomain_019e78f5-a4c1-7ae9-9483-c374839aa2f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_ChemistryTechnologiesSegmentMember_019e78f5-a4c1-7246-ab0a-8a0bf04038f3" xlink:href="ftk-20260630.xsd#ftk_ChemistryTechnologiesSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e78f5-a4c1-7ae9-9483-c374839aa2f4" xlink:to="loc_ftk_ChemistryTechnologiesSegmentMember_019e78f5-a4c1-7246-ab0a-8a0bf04038f3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_DataAnalyticsSegmentMember_019e78f5-a4c1-70c9-b250-d323ee9ace8e" xlink:href="ftk-20260630.xsd#ftk_DataAnalyticsSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e78f5-a4c1-7ae9-9483-c374839aa2f4" xlink:to="loc_ftk_DataAnalyticsSegmentMember_019e78f5-a4c1-70c9-b250-d323ee9ace8e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019e78f5-a4c1-7605-a80c-a93c70a4327d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7056-b8d1-3df316d12ad4" xlink:to="loc_srt_ProductOrServiceAxis_019e78f5-a4c1-7605-a80c-a93c70a4327d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019e78f5-a4c1-7605-a80c-a93c70a4327d_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019e78f5-a4c1-7605-a80c-a93c70a4327d" xlink:to="loc_srt_ProductsAndServicesDomain_019e78f5-a4c1-7605-a80c-a93c70a4327d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019e78f5-a4c1-7a54-baca-1c995b8acc8f" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019e78f5-a4c1-7605-a80c-a93c70a4327d" xlink:to="loc_srt_ProductsAndServicesDomain_019e78f5-a4c1-7a54-baca-1c995b8acc8f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_019e78f5-a4c1-7e6c-8bad-71db5b40641e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e78f5-a4c1-7a54-baca-1c995b8acc8f" xlink:to="loc_us-gaap_ProductMember_019e78f5-a4c1-7e6c-8bad-71db5b40641e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ServiceMember_019e78f5-a4c1-7e2b-81db-50547ab5c3f7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ServiceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e78f5-a4c1-7a54-baca-1c995b8acc8f" xlink:to="loc_us-gaap_ServiceMember_019e78f5-a4c1-7e2b-81db-50547ab5c3f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_RentalMember_019e78f5-a4c1-7d5b-89f7-46a6b26f5c91" xlink:href="ftk-20260630.xsd#ftk_RentalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e78f5-a4c1-7a54-baca-1c995b8acc8f" xlink:to="loc_ftk_RentalMember_019e78f5-a4c1-7d5b-89f7-46a6b26f5c91" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a4c1-7efb-963a-68a2cbbc05ea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7056-b8d1-3df316d12ad4" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a4c1-7efb-963a-68a2cbbc05ea" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-7efb-963a-68a2cbbc05ea_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a4c1-7efb-963a-68a2cbbc05ea" xlink:to="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-7efb-963a-68a2cbbc05ea_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-7075-b098-5b498c845e0c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a4c1-7efb-963a-68a2cbbc05ea" xlink:to="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-7075-b098-5b498c845e0c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonrelatedPartyMember_019e78f5-a4c1-7260-a851-933105236103" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonrelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-7075-b098-5b498c845e0c" xlink:to="loc_us-gaap_NonrelatedPartyMember_019e78f5-a4c1-7260-a851-933105236103" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019e78f5-a4c1-7ef5-b640-3f363dcbc073" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-7075-b098-5b498c845e0c" xlink:to="loc_us-gaap_RelatedPartyMember_019e78f5-a4c1-7ef5-b640-3f363dcbc073" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAbstract_019e78f5-a4c1-7e6e-8ecc-53d37668ba28" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7efd-9ea0-13af719411ac" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAbstract_019e78f5-a4c1-7e6e-8ecc-53d37668ba28" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e78f5-a4c1-76e8-9244-db54330b7b50" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAbstract_019e78f5-a4c1-7e6e-8ecc-53d37668ba28" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e78f5-a4c1-76e8-9244-db54330b7b50" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_019e78f5-a4c1-72e9-9d4c-488b87028e6f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAbstract_019e78f5-a4c1-7e6e-8ecc-53d37668ba28" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_019e78f5-a4c1-72e9-9d4c-488b87028e6f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_019e78f5-a4c1-703d-9d6e-7037740ae0ee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GrossProfit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAbstract_019e78f5-a4c1-7e6e-8ecc-53d37668ba28" xlink:to="loc_us-gaap_GrossProfit_019e78f5-a4c1-703d-9d6e-7037740ae0ee" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_019e78f5-a4c1-7761-af50-1bb5f3cdd156" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAbstract_019e78f5-a4c1-7e6e-8ecc-53d37668ba28" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_019e78f5-a4c1-7761-af50-1bb5f3cdd156" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_AssetAcquisitionTransactionCosts_019f89c2-f93b-797d-87e5-eb1c15a43259" xlink:href="ftk-20260630.xsd#ftk_AssetAcquisitionTransactionCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAbstract_019e78f5-a4c1-7e6e-8ecc-53d37668ba28" xlink:to="loc_ftk_AssetAcquisitionTransactionCosts_019f89c2-f93b-797d-87e5-eb1c15a43259" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingOtherItemAmount_019e78f5-a4c1-7476-ba12-37a19bae8546" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingOtherItemAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAbstract_019e78f5-a4c1-7e6e-8ecc-53d37668ba28" xlink:to="loc_us-gaap_SegmentReportingOtherItemAmount_019e78f5-a4c1-7476-ba12-37a19bae8546" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_019e78f5-a4c1-70c5-91ff-4c98f071f350" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAbstract_019e78f5-a4c1-7e6e-8ecc-53d37668ba28" xlink:to="loc_us-gaap_OperatingIncomeLoss_019e78f5-a4c1-70c5-91ff-4c98f071f350" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseNonoperating_019e78f5-a4c1-7951-a8c5-3100fb1673b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseNonoperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAbstract_019e78f5-a4c1-7e6e-8ecc-53d37668ba28" xlink:to="loc_us-gaap_InterestExpenseNonoperating_019e78f5-a4c1-7951-a8c5-3100fb1673b4" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_019e78f5-a4c1-7fdc-ba28-2f1a8f3f9025" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAbstract_019e78f5-a4c1-7e6e-8ecc-53d37668ba28" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_019e78f5-a4c1-7fdc-ba28-2f1a8f3f9025" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e78f5-a4c1-7915-becf-f0a1165a546d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAbstract_019e78f5-a4c1-7e6e-8ecc-53d37668ba28" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e78f5-a4c1-7915-becf-f0a1165a546d" xlink:type="arc" order="10"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/BusinessSegmentGeographicandMajorCustomerInformationAssetsbyReportableSegmentsDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#BusinessSegmentGeographicandMajorCustomerInformationAssetsbyReportableSegmentsDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/BusinessSegmentGeographicandMajorCustomerInformationAssetsbyReportableSegmentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7dee-ad20-3b3ceaf6d1ef" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7d78-9316-cb0f2c973e21" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7dee-ad20-3b3ceaf6d1ef" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7d78-9316-cb0f2c973e21" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_019e78f5-a4c1-7c6a-b662-0cf7466d4e64" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7d78-9316-cb0f2c973e21" xlink:to="loc_srt_ConsolidationItemsAxis_019e78f5-a4c1-7c6a-b662-0cf7466d4e64" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-7c6a-b662-0cf7466d4e64_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_019e78f5-a4c1-7c6a-b662-0cf7466d4e64" xlink:to="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-7c6a-b662-0cf7466d4e64_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-7d61-8af3-1ed4df298525" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_019e78f5-a4c1-7c6a-b662-0cf7466d4e64" xlink:to="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-7d61-8af3-1ed4df298525" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_019e78f5-a4c1-7d15-b77a-d9691ff54916" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-7d61-8af3-1ed4df298525" xlink:to="loc_us-gaap_OperatingSegmentsMember_019e78f5-a4c1-7d15-b77a-d9691ff54916" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_019e78f5-a4c1-7eb9-acf9-ea01e9f48cee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-7d61-8af3-1ed4df298525" xlink:to="loc_us-gaap_CorporateNonSegmentMember_019e78f5-a4c1-7eb9-acf9-ea01e9f48cee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019e78f5-a4c1-783a-b167-b891dd047366" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7d78-9316-cb0f2c973e21" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019e78f5-a4c1-783a-b167-b891dd047366" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e78f5-a4c1-783a-b167-b891dd047366_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e78f5-a4c1-783a-b167-b891dd047366" xlink:to="loc_us-gaap_SegmentDomain_019e78f5-a4c1-783a-b167-b891dd047366_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e78f5-a4c1-749d-8ca3-ae4f0eac0255" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e78f5-a4c1-783a-b167-b891dd047366" xlink:to="loc_us-gaap_SegmentDomain_019e78f5-a4c1-749d-8ca3-ae4f0eac0255" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_ChemistryTechnologiesSegmentMember_019e78f5-a4c1-74b4-9d0b-d9ff3e31e70a" xlink:href="ftk-20260630.xsd#ftk_ChemistryTechnologiesSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e78f5-a4c1-749d-8ca3-ae4f0eac0255" xlink:to="loc_ftk_ChemistryTechnologiesSegmentMember_019e78f5-a4c1-74b4-9d0b-d9ff3e31e70a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_DataAnalyticsSegmentMember_019e78f5-a4c1-78e9-83e6-876864e610d6" xlink:href="ftk-20260630.xsd#ftk_DataAnalyticsSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e78f5-a4c1-749d-8ca3-ae4f0eac0255" xlink:to="loc_ftk_DataAnalyticsSegmentMember_019e78f5-a4c1-78e9-83e6-876864e610d6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019e78f5-a4c1-7632-b4bc-e2b9c17dba4d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7dee-ad20-3b3ceaf6d1ef" xlink:to="loc_us-gaap_Assets_019e78f5-a4c1-7632-b4bc-e2b9c17dba4d" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/BusinessSegmentGeographicandMajorCustomerInformationAdditionstoLonglivedAssetsDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#BusinessSegmentGeographicandMajorCustomerInformationAdditionstoLonglivedAssetsDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/BusinessSegmentGeographicandMajorCustomerInformationAdditionstoLonglivedAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_019e78f5-a4c1-74df-b5fd-cad420aab75b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_019e78f5-a4c1-7c6c-8f26-cc04b0021217" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_019e78f5-a4c1-74df-b5fd-cad420aab75b" xlink:to="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_019e78f5-a4c1-7c6c-8f26-cc04b0021217" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_019e78f5-a4c1-7355-80c8-e0838a0a89ea" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_019e78f5-a4c1-7c6c-8f26-cc04b0021217" xlink:to="loc_srt_ConsolidationItemsAxis_019e78f5-a4c1-7355-80c8-e0838a0a89ea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-7355-80c8-e0838a0a89ea_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_019e78f5-a4c1-7355-80c8-e0838a0a89ea" xlink:to="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-7355-80c8-e0838a0a89ea_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-79b8-b1fe-9d27ae8a1e6d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_019e78f5-a4c1-7355-80c8-e0838a0a89ea" xlink:to="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-79b8-b1fe-9d27ae8a1e6d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_019e78f5-a4c1-77c9-a6b3-6bc57ff56751" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-79b8-b1fe-9d27ae8a1e6d" xlink:to="loc_us-gaap_OperatingSegmentsMember_019e78f5-a4c1-77c9-a6b3-6bc57ff56751" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_019e78f5-a4c1-72e5-9030-213a950bd13f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019e78f5-a4c1-79b8-b1fe-9d27ae8a1e6d" xlink:to="loc_us-gaap_CorporateNonSegmentMember_019e78f5-a4c1-72e5-9030-213a950bd13f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019e78f5-a4c1-75ec-9a80-94e81d0aa137" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_019e78f5-a4c1-7c6c-8f26-cc04b0021217" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019e78f5-a4c1-75ec-9a80-94e81d0aa137" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e78f5-a4c1-75ec-9a80-94e81d0aa137_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e78f5-a4c1-75ec-9a80-94e81d0aa137" xlink:to="loc_us-gaap_SegmentDomain_019e78f5-a4c1-75ec-9a80-94e81d0aa137_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e78f5-a4c1-7051-a583-54c6bd6eb496" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e78f5-a4c1-75ec-9a80-94e81d0aa137" xlink:to="loc_us-gaap_SegmentDomain_019e78f5-a4c1-7051-a583-54c6bd6eb496" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_ChemistryTechnologiesSegmentMember_019e78f5-a4c1-72b6-a9ea-eaa71123a806" xlink:href="ftk-20260630.xsd#ftk_ChemistryTechnologiesSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e78f5-a4c1-7051-a583-54c6bd6eb496" xlink:to="loc_ftk_ChemistryTechnologiesSegmentMember_019e78f5-a4c1-72b6-a9ea-eaa71123a806" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_DataAnalyticsSegmentMember_019e78f5-a4c1-7553-9d75-1f1de8ee8d3a" xlink:href="ftk-20260630.xsd#ftk_DataAnalyticsSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e78f5-a4c1-7051-a583-54c6bd6eb496" xlink:to="loc_ftk_DataAnalyticsSegmentMember_019e78f5-a4c1-7553-9d75-1f1de8ee8d3a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentExpenditureAdditionToLongLivedAssets_019e78f5-a4c1-7209-893d-125ef640003b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentExpenditureAdditionToLongLivedAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_019e78f5-a4c1-74df-b5fd-cad420aab75b" xlink:to="loc_us-gaap_SegmentExpenditureAdditionToLongLivedAssets_019e78f5-a4c1-7209-893d-125ef640003b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization_019e78f5-a4c1-7110-8a10-76ac3871baed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_019e78f5-a4c1-74df-b5fd-cad420aab75b" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization_019e78f5-a4c1-7110-8a10-76ac3871baed" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/BusinessSegmentGeographicandMajorCustomerInformationGeographicInformationDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#BusinessSegmentGeographicandMajorCustomerInformationGeographicInformationDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/BusinessSegmentGeographicandMajorCustomerInformationGeographicInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_019e78f5-a4c1-7671-83f1-2a444d0fee1b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_019e78f5-a4c1-7f88-9619-1cda442bd0ea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_019e78f5-a4c1-7671-83f1-2a444d0fee1b" xlink:to="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_019e78f5-a4c1-7f88-9619-1cda442bd0ea" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_019e78f5-a4c1-76e4-a8b1-26b77fe850de" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_019e78f5-a4c1-7f88-9619-1cda442bd0ea" xlink:to="loc_srt_StatementGeographicalAxis_019e78f5-a4c1-76e4-a8b1-26b77fe850de" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019e78f5-a4c1-76e4-a8b1-26b77fe850de_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_019e78f5-a4c1-76e4-a8b1-26b77fe850de" xlink:to="loc_srt_SegmentGeographicalDomain_019e78f5-a4c1-76e4-a8b1-26b77fe850de_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019e78f5-a4c1-7d46-b356-9a56701fe775" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_019e78f5-a4c1-76e4-a8b1-26b77fe850de" xlink:to="loc_srt_SegmentGeographicalDomain_019e78f5-a4c1-7d46-b356-9a56701fe775" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_019e78f5-a4c1-72ef-a86d-e35fce337d87" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019e78f5-a4c1-7d46-b356-9a56701fe775" xlink:to="loc_country_US_019e78f5-a4c1-72ef-a86d-e35fce337d87" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_AE_019e78f5-a4c1-7821-ab69-c6e76b301438" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_AE"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019e78f5-a4c1-7d46-b356-9a56701fe775" xlink:to="loc_country_AE_019e78f5-a4c1-7821-ab69-c6e76b301438" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonUsMember_019e78f5-a4c1-716e-8069-261861ea681c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019e78f5-a4c1-7d46-b356-9a56701fe775" xlink:to="loc_us-gaap_NonUsMember_019e78f5-a4c1-716e-8069-261861ea681c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e78f5-a4c1-7be3-9313-2d760efafdb7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_019e78f5-a4c1-7671-83f1-2a444d0fee1b" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e78f5-a4c1-7be3-9313-2d760efafdb7" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/BusinessSegmentGeographicandMajorCustomerInformationMajorCustomersDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#BusinessSegmentGeographicandMajorCustomerInformationMajorCustomersDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/BusinessSegmentGeographicandMajorCustomerInformationMajorCustomersDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7dd7-933e-a4f91b87d0bf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7e4c-9878-e9221e4e62cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7dd7-933e-a4f91b87d0bf" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7e4c-9878-e9221e4e62cb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_019e78f5-a4c1-715b-917f-a8f3af26d32a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7e4c-9878-e9221e4e62cb" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_019e78f5-a4c1-715b-917f-a8f3af26d32a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_019e78f5-a4c1-715b-917f-a8f3af26d32a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_019e78f5-a4c1-715b-917f-a8f3af26d32a" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_019e78f5-a4c1-715b-917f-a8f3af26d32a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_019e78f5-a4c1-7688-bded-063498454319" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_019e78f5-a4c1-715b-917f-a8f3af26d32a" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_019e78f5-a4c1-7688-bded-063498454319" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_019e78f5-a4c1-722a-af05-600b71327936" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_019e78f5-a4c1-7688-bded-063498454319" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_019e78f5-a4c1-722a-af05-600b71327936" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e78f5-a4c1-73d2-bd60-78d3d5ef477e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7e4c-9878-e9221e4e62cb" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e78f5-a4c1-73d2-bd60-78d3d5ef477e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e78f5-a4c1-73d2-bd60-78d3d5ef477e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e78f5-a4c1-73d2-bd60-78d3d5ef477e" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e78f5-a4c1-73d2-bd60-78d3d5ef477e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e78f5-a4c1-7972-b9c0-decdaa22efd5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e78f5-a4c1-73d2-bd60-78d3d5ef477e" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e78f5-a4c1-7972-b9c0-decdaa22efd5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesRevenueNetMember_019e78f5-a4c1-75c9-aff0-3dc6331caadc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SalesRevenueNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e78f5-a4c1-7972-b9c0-decdaa22efd5" xlink:to="loc_us-gaap_SalesRevenueNetMember_019e78f5-a4c1-75c9-aff0-3dc6331caadc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableMember_019e78f5-a4c1-7df5-b7f4-2bec2d446044" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e78f5-a4c1-7972-b9c0-decdaa22efd5" xlink:to="loc_us-gaap_AccountsReceivableMember_019e78f5-a4c1-7df5-b7f4-2bec2d446044" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_019e78f5-a4c1-739e-a6fa-3916919c21cc" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7e4c-9878-e9221e4e62cb" xlink:to="loc_srt_MajorCustomersAxis_019e78f5-a4c1-739e-a6fa-3916919c21cc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_019e78f5-a4c1-739e-a6fa-3916919c21cc_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_019e78f5-a4c1-739e-a6fa-3916919c21cc" xlink:to="loc_srt_NameOfMajorCustomerDomain_019e78f5-a4c1-739e-a6fa-3916919c21cc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_019e78f5-a4c1-77e5-b57f-342df91979c6" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_019e78f5-a4c1-739e-a6fa-3916919c21cc" xlink:to="loc_srt_NameOfMajorCustomerDomain_019e78f5-a4c1-77e5-b57f-342df91979c6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_CustomerAMember_019e78f5-a4c1-73a8-8186-eba3c9363188" xlink:href="ftk-20260630.xsd#ftk_CustomerAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_019e78f5-a4c1-77e5-b57f-342df91979c6" xlink:to="loc_ftk_CustomerAMember_019e78f5-a4c1-73a8-8186-eba3c9363188" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_CustomerBMember_019f89ff-5beb-7ddd-94a3-ee8e481ee9e5" xlink:href="ftk-20260630.xsd#ftk_CustomerBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_019e78f5-a4c1-77e5-b57f-342df91979c6" xlink:to="loc_ftk_CustomerBMember_019f89ff-5beb-7ddd-94a3-ee8e481ee9e5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_CustomerCMember_019fac6f-1080-7aa5-b1ee-858b6d26f118" xlink:href="ftk-20260630.xsd#ftk_CustomerCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_019e78f5-a4c1-77e5-b57f-342df91979c6" xlink:to="loc_ftk_CustomerCMember_019fac6f-1080-7aa5-b1ee-858b6d26f118" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a4c1-7bd1-bfdb-44f26d97ae1a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7e4c-9878-e9221e4e62cb" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a4c1-7bd1-bfdb-44f26d97ae1a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-7bd1-bfdb-44f26d97ae1a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a4c1-7bd1-bfdb-44f26d97ae1a" xlink:to="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-7bd1-bfdb-44f26d97ae1a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-7500-b894-b2ac8a4ae4f1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e78f5-a4c1-7bd1-bfdb-44f26d97ae1a" xlink:to="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-7500-b894-b2ac8a4ae4f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019e78f5-a4c1-7593-a8ed-8fffcc54c145" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e78f5-a4c1-7500-b894-b2ac8a4ae4f1" xlink:to="loc_us-gaap_RelatedPartyMember_019e78f5-a4c1-7593-a8ed-8fffcc54c145" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e78f5-a4c1-71dd-a0f7-06cf1e204e45" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7dd7-933e-a4f91b87d0bf" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e78f5-a4c1-71dd-a0f7-06cf1e204e45" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_019e78f5-a4c1-7eda-bd9a-6e4df9acabc4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7dd7-933e-a4f91b87d0bf" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_019e78f5-a4c1-7eda-bd9a-6e4df9acabc4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_019e78f5-a4c1-7178-8756-592851169e98" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7dd7-933e-a4f91b87d0bf" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_019e78f5-a4c1-7178-8756-592851169e98" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/BusinessSegmentGeographicandMajorCustomerInformationMajorSuppliersDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#BusinessSegmentGeographicandMajorCustomerInformationMajorSuppliersDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/BusinessSegmentGeographicandMajorCustomerInformationMajorSuppliersDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7cb7-a48f-470c72b27b0e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7af8-9e03-79be98ac9476" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7cb7-a48f-470c72b27b0e" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7af8-9e03-79be98ac9476" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_019e78f5-a4c1-7e8e-b57f-0be9c0f3138d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7af8-9e03-79be98ac9476" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_019e78f5-a4c1-7e8e-b57f-0be9c0f3138d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_019e78f5-a4c1-7e8e-b57f-0be9c0f3138d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_019e78f5-a4c1-7e8e-b57f-0be9c0f3138d" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_019e78f5-a4c1-7e8e-b57f-0be9c0f3138d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_019e78f5-a4c1-7c00-9cfb-514207cfdb09" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_019e78f5-a4c1-7e8e-b57f-0be9c0f3138d" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_019e78f5-a4c1-7c00-9cfb-514207cfdb09" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplierConcentrationRiskMember_019e78f5-a4c1-7eac-a299-76a6e342ff7e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SupplierConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_019e78f5-a4c1-7c00-9cfb-514207cfdb09" xlink:to="loc_us-gaap_SupplierConcentrationRiskMember_019e78f5-a4c1-7eac-a299-76a6e342ff7e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionBySupplierAxis_019e78f5-a4c1-769c-9ed4-84348076e165" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionBySupplierAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7af8-9e03-79be98ac9476" xlink:to="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionBySupplierAxis_019e78f5-a4c1-769c-9ed4-84348076e165" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_019e78f5-a4c1-769c-9ed4-84348076e165_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionBySupplierAxis_019e78f5-a4c1-769c-9ed4-84348076e165" xlink:to="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_019e78f5-a4c1-769c-9ed4-84348076e165_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_019e78f5-a4c1-772a-90d4-ec1e8eb16a6e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionBySupplierAxis_019e78f5-a4c1-769c-9ed4-84348076e165" xlink:to="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_019e78f5-a4c1-772a-90d4-ec1e8eb16a6e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_SupplierAMember_019e78f5-a4c1-729b-86a1-491595151c2b" xlink:href="ftk-20260630.xsd#ftk_SupplierAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_019e78f5-a4c1-772a-90d4-ec1e8eb16a6e" xlink:to="loc_ftk_SupplierAMember_019e78f5-a4c1-729b-86a1-491595151c2b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_SupplierBMember_019e78f5-a4c1-7198-8be9-8deb38ad5fae" xlink:href="ftk-20260630.xsd#ftk_SupplierBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_019e78f5-a4c1-772a-90d4-ec1e8eb16a6e" xlink:to="loc_ftk_SupplierBMember_019e78f5-a4c1-7198-8be9-8deb38ad5fae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_SupplierCMember_019e78f5-a4c1-77b7-b718-f1835eee5494" xlink:href="ftk-20260630.xsd#ftk_SupplierCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_019e78f5-a4c1-772a-90d4-ec1e8eb16a6e" xlink:to="loc_ftk_SupplierCMember_019e78f5-a4c1-77b7-b718-f1835eee5494" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_SupplierDMember_019e78f5-a4c1-73e0-bb64-e479565ae32a" xlink:href="ftk-20260630.xsd#ftk_SupplierDMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_019e78f5-a4c1-772a-90d4-ec1e8eb16a6e" xlink:to="loc_ftk_SupplierDMember_019e78f5-a4c1-73e0-bb64-e479565ae32a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e78f5-a4c1-7d3c-875b-0e49a08c7936" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e78f5-a4c1-7af8-9e03-79be98ac9476" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e78f5-a4c1-7d3c-875b-0e49a08c7936" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e78f5-a4c1-7d3c-875b-0e49a08c7936_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e78f5-a4c1-7d3c-875b-0e49a08c7936" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e78f5-a4c1-7d3c-875b-0e49a08c7936_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e78f5-a4c1-7c19-99fd-9c64165083e4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e78f5-a4c1-7d3c-875b-0e49a08c7936" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e78f5-a4c1-7c19-99fd-9c64165083e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsSegmentMember_019e78f5-a4c1-7ecc-ad3a-4279a85d9def" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e78f5-a4c1-7c19-99fd-9c64165083e4" xlink:to="loc_us-gaap_CostOfGoodsSegmentMember_019e78f5-a4c1-7ecc-ad3a-4279a85d9def" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SuppliesExpense_019e78f5-a4c1-7f47-a70f-17fb2612a48b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SuppliesExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7cb7-a48f-470c72b27b0e" xlink:to="loc_us-gaap_SuppliesExpense_019e78f5-a4c1-7f47-a70f-17fb2612a48b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_019e78f5-a4c1-7a94-8813-5bc38417ecf2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e78f5-a4c1-7cb7-a48f-470c72b27b0e" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_019e78f5-a4c1-7a94-8813-5bc38417ecf2" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://flotekind.com/role/SubsequentEventDetails" xlink:type="simple" xlink:href="ftk-20260630.xsd#SubsequentEventDetails"/>
  <link:definitionLink xlink:role="http://flotekind.com/role/SubsequentEventDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_019e78f5-a4c1-77ae-bb5a-deca6dac92da" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_019e78f5-a4c1-71bd-87bb-db4704731572" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_019e78f5-a4c1-77ae-bb5a-deca6dac92da" xlink:to="loc_us-gaap_SubsequentEventTable_019e78f5-a4c1-71bd-87bb-db4704731572" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_019e78f5-a4c1-71a5-819a-b48b50f2998e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_019e78f5-a4c1-71bd-87bb-db4704731572" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_019e78f5-a4c1-71a5-819a-b48b50f2998e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019e78f5-a4c1-71a5-819a-b48b50f2998e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019e78f5-a4c1-71a5-819a-b48b50f2998e" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019e78f5-a4c1-71a5-819a-b48b50f2998e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019e78f5-a4c1-7e22-9e62-138653a3bbd8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019e78f5-a4c1-71a5-819a-b48b50f2998e" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019e78f5-a4c1-7e22-9e62-138653a3bbd8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_019e78f5-a4c1-77cd-9623-32204f3d1e1a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_019e78f5-a4c1-7e22-9e62-138653a3bbd8" xlink:to="loc_us-gaap_SubsequentEventMember_019e78f5-a4c1-77cd-9623-32204f3d1e1a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_TypeOfContractAxis_019fcfec-273b-7b74-8830-d7067103ca6d" xlink:href="ftk-20260630.xsd#ftk_TypeOfContractAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_019e78f5-a4c1-71bd-87bb-db4704731572" xlink:to="loc_ftk_TypeOfContractAxis_019fcfec-273b-7b74-8830-d7067103ca6d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_TypeOfContractDomain_019fcfec-273b-7b74-8830-d7067103ca6d_default" xlink:href="ftk-20260630.xsd#ftk_TypeOfContractDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ftk_TypeOfContractAxis_019fcfec-273b-7b74-8830-d7067103ca6d" xlink:to="loc_ftk_TypeOfContractDomain_019fcfec-273b-7b74-8830-d7067103ca6d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_TypeOfContractDomain_019fcfec-273b-774c-a3e9-6097e806b09e" xlink:href="ftk-20260630.xsd#ftk_TypeOfContractDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ftk_TypeOfContractAxis_019fcfec-273b-7b74-8830-d7067103ca6d" xlink:to="loc_ftk_TypeOfContractDomain_019fcfec-273b-774c-a3e9-6097e806b09e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_PREPAMember_019fcfec-7aa7-7282-8347-a62b0c6b0a8a" xlink:href="ftk-20260630.xsd#ftk_PREPAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ftk_TypeOfContractDomain_019fcfec-273b-774c-a3e9-6097e806b09e" xlink:to="loc_ftk_PREPAMember_019fcfec-7aa7-7282-8347-a62b0c6b0a8a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementScenarioAxis_019fd02f-ef9e-7e35-9963-228cb52888c0" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementScenarioAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_019e78f5-a4c1-71bd-87bb-db4704731572" xlink:to="loc_srt_StatementScenarioAxis_019fd02f-ef9e-7e35-9963-228cb52888c0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_019fd02f-ef9e-7e35-9963-228cb52888c0_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_019fd02f-ef9e-7e35-9963-228cb52888c0" xlink:to="loc_srt_ScenarioUnspecifiedDomain_019fd02f-ef9e-7e35-9963-228cb52888c0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_019fd02f-ef9e-7859-832b-08a7d70b1b57" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_019fd02f-ef9e-7e35-9963-228cb52888c0" xlink:to="loc_srt_ScenarioUnspecifiedDomain_019fd02f-ef9e-7859-832b-08a7d70b1b57" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScenarioPlanMember_019fd02f-ef9e-7312-ad64-0ff86244baf5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScenarioPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_019fd02f-ef9e-7859-832b-08a7d70b1b57" xlink:to="loc_us-gaap_ScenarioPlanMember_019fd02f-ef9e-7312-ad64-0ff86244baf5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioForecastMember_019fd030-bab8-70ab-9fc0-812e90daec6d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScenarioForecastMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_019fd02f-ef9e-7859-832b-08a7d70b1b57" xlink:to="loc_srt_ScenarioForecastMember_019fd030-bab8-70ab-9fc0-812e90daec6d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_RevenueFromContractWithCustomerRevenueBacklogPeriodOfTime_019fcfec-7e6b-75eb-acbf-07402cc6f373" xlink:href="ftk-20260630.xsd#ftk_RevenueFromContractWithCustomerRevenueBacklogPeriodOfTime"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019e78f5-a4c1-77ae-bb5a-deca6dac92da" xlink:to="loc_ftk_RevenueFromContractWithCustomerRevenueBacklogPeriodOfTime_019fcfec-7e6b-75eb-acbf-07402cc6f373" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromCollaborativeArrangementExcludingRevenueFromContractWithCustomer_019fcfec-273b-7645-8ef6-905419bc99c6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromCollaborativeArrangementExcludingRevenueFromContractWithCustomer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019e78f5-a4c1-77ae-bb5a-deca6dac92da" xlink:to="loc_us-gaap_RevenueFromCollaborativeArrangementExcludingRevenueFromContractWithCustomer_019fcfec-273b-7645-8ef6-905419bc99c6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019fd02f-ef9e-779b-939f-cd18c38e6c12" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019e78f5-a4c1-77ae-bb5a-deca6dac92da" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019fd02f-ef9e-779b-939f-cd18c38e6c12" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/srt/role/srt-eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-roles-2026.xsd#eedm1"/>
  <link:definitionLink xlink:role="http://fasb.org/srt/role/srt-eedm/ExtensibleEnumerationLists" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_ftk_RightOfUseAsset_019e78f5-a1a8-7d0a-8f46-fb118e463411" xlink:href="ftk-20260630.xsd#ftk_RightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract" xlink:to="loc_ftk_RightOfUseAsset_019e78f5-a1a8-7d0a-8f46-fb118e463411" xlink:type="arc" order="101"/>
  </link:definitionLink>
</link:linkbase>
