Lewis Short
Āpennīnus | Appennīnus (noun M) : (better , Verg. A. 12, 703 Cod. Med.;
* Also APENINVS,Inscr. Grut. 204, 18), , m.from the Celtic penn, mountain - summit, the mountainchain that passes through the length of Italy, the Apennines, Plin. 3, 5, 7, § 48; conspicuous for height; hence, celsus Appenninus, Hor. Epod. 16, 29: Appenninus nubifer,Ov. M. 2, 226.—Personified: gaudetque nivali Vertice se attollens pater Appenninus ad auras,Verg. A. 12, 703; cf. Mann. Ital. 1, 264 sq.
Charlton T. Lewis, Charles Short, A Latin Dictionary