Arnus, i, m., = Ἄρνος,
I a river of Etruria , now the Arno , Plin. 3, 5, 8, § 50; Tac. A. 1, 79 al.; cf. Mann. Ital. I. 328.
II —Hence, Arnĭensis , e, adj., of or pertaining to the Arnus : tribus, situated on the Arnus , acc. to Liv. 6, 5, settled A. U. C. 396, most distant from Rome, as Saburana was the nearest: a Saburană usque ad Arniensem, Cic. Agr. 2, 29.