Lewis Short
Āternus | Āter-num, i (noun M.n) : Ἄτερνος
* A river in Samnium emptying into the Adriatic Sea, now Pescara, Plin. 3, 5, 6, § 44; 3, 12, 17, § 106.—At its mouth was the town , , , = Ἄτερνον, named after it, now also called Pescara, Liv. 24, 47; cf. Mann. Ital. I. p. 468.—Hence, Aternensis ager,Front. Col. p. 120 Goes.
Charlton T. Lewis, Charles Short, A Latin Dictionary