Lewis Short
Arna | Arnātes, um (noun F.m) :
* A town in Umbria, a mile east of Perusia, now Civitella d'Arno, Sil. 8, 458; Inscr. Orell. 91; cf. Mann. Ital. I. 483.—Hence, , , , the inhabitants of Arna, Plin. 3, 14, 19, § 113; Inscr. Orell. 90 and 5005.
Charlton T. Lewis, Charles Short, A Latin Dictionary