Entry 1 sense Webster, 1913 Oliva /ōl-ēv'-ə/ · O·li·va · IPA /oʊlˈiːvə/ 01 n. A genus of polished marine gastropod shells, chiefly tropical, and often beautifully colored. 1. A genus of polished marine gastropod shells, chiefly tropical, and often beautifully colored.(Zool.)