Lewis & Short

Ămĭternum, i, n. [acc. to Varr. L. L. 5, 5, 12, from am- = amb- and Aternus], = Ἀμίτερνον, a very ancient town built by the Aborigines, in the Sabine country, now San Vettorino; cf. Mann. Ital. 1, 509; the birthplace of the historian Sallust.
Derivv.

  1. A. Ămĭternīnus, a, um, adj., belonging to Amiternum, Col. 10, 422.—Ămĭ-ternīni, ōrum, m. subst., its inhabitants, Varr. L. L. 5, 28, p. 11 Müll.; Liv. 28, 45, 19; Plin. 3, 12, 17, § 107.
  2. B. Ămĭternus, a, um, adj., poet. for Amiterninus: cohors, Verg. A. 7, 710: ager, Mart. 13, 20.