Entry 1 sense Webster, 1913 Acanthopterygian · Ac·an·thop·ter·yg·i·an · IPA /ˌæk.ænˌθɑp.təˈɹɪd͡ʒ.i.n̩/ 01 a. Belonging to the order of fishes having spinose fins, as the perch. 1. Belonging to the order of fishes having spinose fins, as the perch.(Zool.)