Lewis & Short

Mĕtaurensis, e, adj. [Metaurus], of or belonging to the river Metaurus, in Umbria: AGER, Inscr. Oliv. Marm. Pisaur. n. 30.
Subst.: Mĕtaurenses, ĭum, m., the inhabitants of that region, Metaurians, Plin. 3, 14, 19, § 114.