exobiology Syllabification: (ex·o·bi·ol·o·gy)Pronunciation: /ˌeksōbīˈäləjē/Definition of exobiology noun the branch of science that deals with the possibility and likely nature of life on other planets or in space. Derivatives exobiologicalPronunciation: /-ˌbīəˈläjikəl/ adjective exobiologistPronunciation: /-jist/ noun exobiology in other Oxford dictionaries Definition of exobiology in the British & World English dictionary