Lewis Short
(adjective) : dĕcennis, e, id.
* Of ten years (post-Aug.): bellum, of the Greeks before Troy,Quint. 8, 4, 22; also proelium,Petr. 89, 2, 8: obsidio (Veiorum),Flor. 1, 12, 8: equae,ten years old,Plin. 8, 44, 69; cf.: decenni major asinus,Pall. Mart. 14, 1.
* Subst.: decennia, ium, n., = decennalia, a festival under the emperors, held every ten years, Treb. Gall. 5 fin.; cf.: decennalis, no. II.
Charlton T. Lewis, Charles Short, A Latin Dictionary