<?xml version="1.0" encoding="us-ascii" standalone="yes"?>
<!--XBRL Document Created with XBRLMaster-->
<!--Version: 2.3.08-->
<!--Based on XBRL 2.1-->
<!--Date of creation: 09/17/2026-->
<!--Software architectural design and coding: A'c Dharmapremananda Avt.-->
<!--Copyright (c) 2026 I-NET Business Solutions, Inc. All Rights Reserved.-->
<link:linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" 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:roleRef roleURI="http://ctth.com/role/Cover" xlink:href="ctth-20260630.xsd#Cover" xlink:type="simple" />
  <link:roleRef roleURI="http://ctth.com/role/BalanceSheets" xlink:href="ctth-20260630.xsd#BalanceSheets" xlink:type="simple" />
  <link:roleRef roleURI="http://ctth.com/role/BalanceSheetsParenthetical" xlink:href="ctth-20260630.xsd#BalanceSheetsParenthetical" xlink:type="simple" />
  <link:roleRef roleURI="http://ctth.com/role/IncomeStatements" xlink:href="ctth-20260630.xsd#IncomeStatements" xlink:type="simple" />
  <link:roleRef roleURI="http://ctth.com/role/StatementsOfStockholdersEquity" xlink:href="ctth-20260630.xsd#StatementsOfStockholdersEquity" xlink:type="simple" />
  <link:roleRef roleURI="http://ctth.com/role/StatementsOfCashFlow" xlink:href="ctth-20260630.xsd#StatementsOfCashFlow" xlink:type="simple" />
  <link:roleRef roleURI="http://ctth.com/role/NatureOfOperations" xlink:href="ctth-20260630.xsd#NatureOfOperations" xlink:type="simple" />
  <link:roleRef roleURI="http://ctth.com/role/SummaryOfSignificantAccountingPolicies" xlink:href="ctth-20260630.xsd#SummaryOfSignificantAccountingPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://ctth.com/role/GoingConcern" xlink:href="ctth-20260630.xsd#GoingConcern" xlink:type="simple" />
  <link:roleRef roleURI="http://ctth.com/role/ComparativeFinancialStatements" xlink:href="ctth-20260630.xsd#ComparativeFinancialStatements" xlink:type="simple" />
  <link:roleRef roleURI="http://ctth.com/role/StockholdersEquity" xlink:href="ctth-20260630.xsd#StockholdersEquity" xlink:type="simple" />
  <link:roleRef roleURI="http://ctth.com/role/IntangibleAssets" xlink:href="ctth-20260630.xsd#IntangibleAssets" xlink:type="simple" />
  <link:roleRef roleURI="http://ctth.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:href="ctth-20260630.xsd#SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://ctth.com/role/IntangibleAssetsTables" xlink:href="ctth-20260630.xsd#IntangibleAssetsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://ctth.com/role/SummaryOfSignificantAccountingPoliciesDetailsNarrative" xlink:href="ctth-20260630.xsd#SummaryOfSignificantAccountingPoliciesDetailsNarrative" xlink:type="simple" />
  <link:roleRef roleURI="http://ctth.com/role/StockholdersEquityDetailsNarrative" xlink:href="ctth-20260630.xsd#StockholdersEquityDetailsNarrative" xlink:type="simple" />
  <link:roleRef roleURI="http://ctth.com/role/IntangibleAssetsDetails" xlink:href="ctth-20260630.xsd#IntangibleAssetsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://ctth.com/role/IntangibleAssetsDetails1" xlink:href="ctth-20260630.xsd#IntangibleAssetsDetails1" xlink:type="simple" />
  <link:roleRef roleURI="http://ctth.com/role/IntangibleAssetsDetailsNarrative" xlink:href="ctth-20260630.xsd#IntangibleAssetsDetailsNarrative" xlink:type="simple" />
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" />
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" />
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" />
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" arcroleURI="http://xbrl.org/int/dim/arcrole/all" />
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#notAll" arcroleURI="http://xbrl.org/int/dim/arcrole/notAll" />
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" />
  <link:definitionLink xlink:type="extended" xlink:role="http://ctth.com/role/Cover" xlink:title="00000001 - Document - Cover Page Information">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_CoverAbstract" xlink:label="loc_deiCover" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://ctth.com/role/BalanceSheets" xlink:title="110200 - Statement - Balance Sheets" />
  <link:definitionLink xlink:type="extended" xlink:role="http://ctth.com/role/BalanceSheetsParenthetical" xlink:title="110201 - Statement - Balance Sheets (Parenthetical)" />
  <link:definitionLink xlink:type="extended" xlink:role="http://ctth.com/role/IncomeStatements" xlink:title="124100 - Statement - Income Statements" />
  <link:definitionLink xlink:type="extended" xlink:role="http://ctth.com/role/StatementsOfStockholdersEquity" xlink:title="148600 - Statement - Statements of Stockholders Equity">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" order="2000" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaapStatementEquityComponentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapStatementEquityComponentsAxis" order="1020" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain" order="1030" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain_10" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain_10" order="1040" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaapCommonStockMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapCommonStockMember" order="1021" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockCommonMember" xlink:label="loc_us-gaapTreasuryStockCommonMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapTreasuryStockCommonMember" order="1022" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="loc_us-gaapAdditionalPaidInCapitalMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapAdditionalPaidInCapitalMember" order="1023" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaapRetainedEarningsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapRetainedEarningsMember" order="1024" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharesIssued" xlink:label="loc_us-gaapSharesIssued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSharesIssued" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaapStockholdersEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockholdersEquity" order="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaapNetIncomeLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapNetIncomeLoss" order="3" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesIssuedForServices" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesIssuedForServices" order="4" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodValueIssuedForServices" xlink:label="loc_us-gaapStockIssuedDuringPeriodValueIssuedForServices" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodValueIssuedForServices" order="5" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_StockIssuedDuringPeriodSharesIssuedForCash" xlink:label="loc_ctthStockIssuedDuringPeriodSharesIssuedForCash" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_ctthStockIssuedDuringPeriodSharesIssuedForCash" order="6" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_StockIssuedDuringPeriodValueIssuedForCash" xlink:label="loc_ctthStockIssuedDuringPeriodValueIssuedForCash" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_ctthStockIssuedDuringPeriodValueIssuedForCash" order="7" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://ctth.com/role/StatementsOfCashFlow" xlink:title="170000 - Statement - Statements of Cash Flow" />
  <link:definitionLink xlink:type="extended" xlink:role="http://ctth.com/role/NatureOfOperations" xlink:title="995446 - Disclosure - NATURE OF OPERATIONS" />
  <link:definitionLink xlink:type="extended" xlink:role="http://ctth.com/role/SummaryOfSignificantAccountingPolicies" xlink:title="995447 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES" />
  <link:definitionLink xlink:type="extended" xlink:role="http://ctth.com/role/GoingConcern" xlink:title="995448 - Disclosure - GOING CONCERN" />
  <link:definitionLink xlink:type="extended" xlink:role="http://ctth.com/role/ComparativeFinancialStatements" xlink:title="995449 - Disclosure - COMPARATIVE FINANCIAL STATEMENTS" />
  <link:definitionLink xlink:type="extended" xlink:role="http://ctth.com/role/StockholdersEquity" xlink:title="995450 - Disclosure - STOCKHOLDERS EQUITY" />
  <link:definitionLink xlink:type="extended" xlink:role="http://ctth.com/role/IntangibleAssets" xlink:title="995451 - Disclosure - INTANGIBLE ASSETS" />
  <link:definitionLink xlink:type="extended" xlink:role="http://ctth.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:title="995452 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)" />
  <link:definitionLink xlink:type="extended" xlink:role="http://ctth.com/role/IntangibleAssetsTables" xlink:title="995453 - Disclosure - INTANGIBLE ASSETS (Tables)" />
  <link:definitionLink xlink:type="extended" xlink:role="http://ctth.com/role/SummaryOfSignificantAccountingPoliciesDetailsNarrative" xlink:title="995454 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details Narrative)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" order="2000" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsByMajorClassAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsByMajorClassAxis" order="1020" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain" order="1030" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain_10" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain_10" order="1040" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TrademarksMember" xlink:label="loc_us-gaapTrademarksMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="loc_us-gaapTrademarksMember" order="1021" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PatentsMember" xlink:label="loc_us-gaapPatentsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="loc_us-gaapPatentsMember" order="1022" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_IntangibleAssetsUsefulLife" xlink:label="loc_ctthIntangibleAssetsUsefulLife" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_ctthIntangibleAssetsUsefulLife" order="1" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://ctth.com/role/StockholdersEquityDetailsNarrative" xlink:title="995455 - Disclosure - STOCKHOLDERS EQUITY (Details Narrative)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" order="2000" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_TitleOfIndividualAxis" xlink:label="loc_srtTitleOfIndividualAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtTitleOfIndividualAxis" order="1020" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtTitleOfIndividualAxis" xlink:to="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" order="1030" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_srtTitleOfIndividualWithRelationshipToEntityDomain_10" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srtTitleOfIndividualAxis" xlink:to="loc_srtTitleOfIndividualWithRelationshipToEntityDomain_10" order="1040" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionAxis" xlink:label="loc_us-gaapRelatedPartyTransactionAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapRelatedPartyTransactionAxis" order="1040" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaapRelatedPartyTransactionDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapRelatedPartyTransactionAxis" xlink:to="loc_us-gaapRelatedPartyTransactionDomain" order="1050" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaapRelatedPartyTransactionDomain_10" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaapRelatedPartyTransactionAxis" xlink:to="loc_us-gaapRelatedPartyTransactionDomain_10" order="1060" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_KatherineColeMember" xlink:label="loc_ctthKatherineColeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:to="loc_ctthKatherineColeMember" order="1041" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_RyanKhouriMember" xlink:label="loc_ctthRyanKhouriMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:to="loc_ctthRyanKhouriMember" order="1042" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_AllenGreenspoonMember" xlink:label="loc_ctthAllenGreenspoonMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:to="loc_ctthAllenGreenspoonMember" order="1043" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_JohnJenneweinMember" xlink:label="loc_ctthJohnJenneweinMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:to="loc_ctthJohnJenneweinMember" order="1044" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_PetroCzupielMember" xlink:label="loc_ctthPetroCzupielMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:to="loc_ctthPetroCzupielMember" order="1045" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_MurrayGoldenbergMember" xlink:label="loc_ctthMurrayGoldenbergMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:to="loc_ctthMurrayGoldenbergMember" order="1046" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_BordersConsultingLLCMember" xlink:label="loc_ctthBordersConsultingLLCMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyTransactionDomain" xlink:to="loc_ctthBordersConsultingLLCMember" order="1047" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_FrankHaritonMember" xlink:label="loc_ctthFrankHaritonMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:to="loc_ctthFrankHaritonMember" order="1048" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_KevinSakserMember" xlink:label="loc_ctthKevinSakserMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:to="loc_ctthKevinSakserMember" order="1049" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:label="loc_us-gaapPreferredStockSharesAuthorized" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockSharesAuthorized" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PreferredStockSharesIssued" xlink:label="loc_us-gaapPreferredStockSharesIssued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockSharesIssued" order="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PreferredStockSharesOutstanding" xlink:label="loc_us-gaapPreferredStockSharesOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockSharesOutstanding" order="3" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="loc_us-gaapCommonStockSharesAuthorized" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockSharesAuthorized" order="4" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockSharesIssued" xlink:label="loc_us-gaapCommonStockSharesIssued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockSharesIssued" order="5" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="loc_us-gaapCommonStockSharesOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockSharesOutstanding" order="6" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesNewIssues" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesNewIssues" order="7" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_StockIssuedDuringPeriodSharesIssuedForCash" xlink:label="loc_ctthStockIssuedDuringPeriodSharesIssuedForCash" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_ctthStockIssuedDuringPeriodSharesIssuedForCash" order="8" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_StockIssuedDuringPeriodValueIssuedForCash" xlink:label="loc_ctthStockIssuedDuringPeriodValueIssuedForCash" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_ctthStockIssuedDuringPeriodValueIssuedForCash" order="9" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesIssuedForServices" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesIssuedForServices" order="10" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodValueIssuedForServices" xlink:label="loc_us-gaapStockIssuedDuringPeriodValueIssuedForServices" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodValueIssuedForServices" order="11" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://ctth.com/role/IntangibleAssetsDetails" xlink:title="995456 - Disclosure - INTANGIBLE ASSETS (Details)" />
  <link:definitionLink xlink:type="extended" xlink:role="http://ctth.com/role/IntangibleAssetsDetails1" xlink:title="995457 - Disclosure - INTANGIBLE ASSETS (Details 1)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" order="2000" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GeographicDistributionAxis" xlink:label="loc_us-gaapGeographicDistributionAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapGeographicDistributionAxis" order="1020" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GeographicDistributionDomain" xlink:label="loc_us-gaapGeographicDistributionDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapGeographicDistributionAxis" xlink:to="loc_us-gaapGeographicDistributionDomain" order="1030" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GeographicDistributionDomain" xlink:label="loc_us-gaapGeographicDistributionDomain_10" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaapGeographicDistributionAxis" xlink:to="loc_us-gaapGeographicDistributionDomain_10" order="1040" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_UsCountryMember" xlink:label="loc_ctthUsCountryMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapGeographicDistributionDomain" xlink:to="loc_ctthUsCountryMember" order="1021" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_CanadaCountryMember" xlink:label="loc_ctthCanadaCountryMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapGeographicDistributionDomain" xlink:to="loc_ctthCanadaCountryMember" order="1022" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_UsOneCountryMember" xlink:label="loc_ctthUsOneCountryMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapGeographicDistributionDomain" xlink:to="loc_ctthUsOneCountryMember" order="1023" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_CanadaOneCountryMember" xlink:label="loc_ctthCanadaOneCountryMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapGeographicDistributionDomain" xlink:to="loc_ctthCanadaOneCountryMember" order="1024" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_UsTwoCountryMember" xlink:label="loc_ctthUsTwoCountryMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapGeographicDistributionDomain" xlink:to="loc_ctthUsTwoCountryMember" order="1025" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_EuropeCountryMember" xlink:label="loc_ctthEuropeCountryMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapGeographicDistributionDomain" xlink:to="loc_ctthEuropeCountryMember" order="1026" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_MexicoCountryMember" xlink:label="loc_ctthMexicoCountryMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapGeographicDistributionDomain" xlink:to="loc_ctthMexicoCountryMember" order="1027" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_PatentNumberDescription" xlink:label="loc_ctthPatentNumberDescription" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_ctthPatentNumberDescription" order="1" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_FileDateDescription" xlink:label="loc_ctthFileDateDescription" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_ctthFileDateDescription" order="2" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_ExpirationDateDescription" xlink:label="loc_ctthExpirationDateDescription" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_ctthExpirationDateDescription" order="3" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://ctth.com/role/IntangibleAssetsDetailsNarrative" xlink:title="995458 - Disclosure - INTANGIBLE ASSETS (Details Narrative)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" order="2000" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GeographicDistributionAxis" xlink:label="loc_us-gaapGeographicDistributionAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapGeographicDistributionAxis" order="1010" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GeographicDistributionDomain" xlink:label="loc_us-gaapGeographicDistributionDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapGeographicDistributionAxis" xlink:to="loc_us-gaapGeographicDistributionDomain" order="1020" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GeographicDistributionDomain" xlink:label="loc_us-gaapGeographicDistributionDomain_10" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaapGeographicDistributionAxis" xlink:to="loc_us-gaapGeographicDistributionDomain_10" order="1030" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_UsCountryMember" xlink:label="loc_ctthUsCountryMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapGeographicDistributionDomain" xlink:to="loc_ctthUsCountryMember" order="1011" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_CanadaCountryMember" xlink:label="loc_ctthCanadaCountryMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapGeographicDistributionDomain" xlink:to="loc_ctthCanadaCountryMember" order="1012" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_UsOneCountryMember" xlink:label="loc_ctthUsOneCountryMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapGeographicDistributionDomain" xlink:to="loc_ctthUsOneCountryMember" order="1013" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="loc_us-gaapAmortizationOfIntangibleAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAmortizationOfIntangibleAssets" order="1" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_TrademarkFileDateDescription" xlink:label="loc_ctthTrademarkFileDateDescription" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_ctthTrademarkFileDateDescription" order="2" />
    <link:loc xlink:type="locator" xlink:href="ctth-20260630.xsd#ctth_TrademarkExpirationDateDescription" xlink:label="loc_ctthTrademarkExpirationDateDescription" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_ctthTrademarkExpirationDateDescription" order="3" />
  </link:definitionLink>
</link:linkbase>
