triacanthoid,a.andn.Ichth.|traɪəˈkænθɔɪd| [f.mod.L. Triacanthus, generic name (f.Gr. τρι-, tri- + ἄκανθα spine) + -oid.] a.adj. Belonging to or having the characters of the family Triacanthidæ of plectognath fishes, typified by the genus Triacanthus. b.n. A fish of this family. 1891in Cent.Dict.