Having a smooth, shining surface, as if polished or enameled: specifically applied to those scales or plates of fishes which are generally of an angular form and composed of a bony or hard horny tissue overlaid with enamel. See cut under scale.Having ganoid scales or plates, as a fish; specifically, of or pertaining to the Ganoidei: as, a ganoid fauna.n. One of the Ganoidei; a fish of the order Ganoidei.