Allĭa (more correct than Alĭa; cf. Wagner, Orthogr. Vergil. p. 415 sq.), ae, f.,
I a little river eleven miles northwards from Rome , near Crustumerium , in the country of the Sabines , passing through a wide plain (cf. Mann. Ital. 1, 520; Müll. Roms Camp. 1, 138; 141 sq.); it was made memorable by the terrible defeat of the Romans by the Gauls A. U. C. 365, XV. Kal. Sextil. (18 July).
II —Hence, Alliensis , e, adj., of or pertaining to Allia: dies, of this battle , considered ever after as a dies nefastus, Liv. 5, 37-39; 6, 1; Cic. Att. 9, 5; Verg. A. 7, 717; Luc. 7, 408; Suet. Vit. 11; cf. Paul. ex Fest. p. 7 Müll.