ovotestis Syllabification: (o·vo·tes·tis)Pronunciation: /ˌōvōˈtestis/Definition of ovotestis noun (plural ovotestes /-ˈtestēz/) Zoology an organ producing both ova and spermatozoa, as in some gastropod mollusks. Origin: late 19th century: from ovum + testisovotestis in other Oxford dictionaries Definition of ovotestis in the British & World English dictionary