insourcing Syllabification: (in·sourc·ing)Pronunciation: /ˈinˌsôrsiNG/Definition of insourcing noun the practice of using an organization’s own personnel or other resources to accomplish a task. Derivatives insource verb Origin: 1970s: on the pattern of outsourcing (see outsource)insourcing in other Oxford dictionaries Definition of insourcing in the British & World English dictionary