microinject Syllabification: (mi·cro·in·ject)Pronunciation: /ˌmīkrō-inˈjekt/Definition of microinject verb [with object] Biology inject (something) into a microscopic object. Derivatives microinjectionPronunciation: /-ˈjekSHən/ noun microinject in other Oxford dictionaries Definition of microinject in the British & World English dictionary