nevus Syllabification: (ne·vus)Pronunciation: /ˈnēvəs/ (Britishnaevus)Definition of nevus noun (plural nevi /-ˌvī/) a birthmark or a mole on the skin, especially a birthmark in the form of a raised red patch. Origin: mid 19th century: from Latinnevus in other Oxford dictionaries Definition of nevus in the British & World English dictionary