Entry 1 sense Webster, 1913 Superfecundation · Su·per·fec·un·da·tion · IPA /ˌsupəɹˌfikənˈdeɪʃən/ 01 n. Fertilization of two ova, at the same menstruation, by two different acts of coition. 1. Fertilization of two ova, at the same menstruation, by two different acts of coition.(Physiol.)