"An extinct ruminant mammal of the family Oreodontidae, known from fossils of the Middle Tertiary period", Mid 19th cent. From scientific Latin Oreodont- (in Oreodontidae: J. Leidy 1869, in Jrnl. Acad. Nat. Sci. Philadelphia 7 71; from oreo- (in Oreodon) + -odont + -idae: see -id).[oreodont etymology, oreodont origin, 英语词源]