trĭĕtērĭcus, a, um, adj., = τριετηρικός,
recurring every three years , triennial : sacra, the festival of Bacchus , Ov. M. 6, 587; also called trieterica orgia, Verg. A. 4, 302. —As subst.: trĭĕtērĭca , ōrum, n., the festival of Bacchus , Ov. R. Am. 593; Stat. Th. 2, 661; id. Achill. 1, 595; Hyg. Fab. 131; cf. trieteris.