geoscience Syllabification: (ge·o·sci·ence)Pronunciation: /ˌjēōˈsīəns, ˈjēōˌsīəns/Definition of geoscience noun (also geosciences) earth sciences, especially geology. Derivatives geoscientistPronunciation: /ˌjēōˈsīəntist, ˈjēōˌsīəntist/ noun geoscience in other Oxford dictionaries Definition of geoscience in the British & World English dictionary