Decennovium

A New Latin Dictionary by Charlton T. Lewis Ph.D. and Charles Short, LL. D.

Dĕcennŏvĭum, ii, n. [decem-novem],

the Pomptine Marshes (19,000 feet in length), Cassiod. Var. 2, 32 sq.; Inscr. Grut. 152, 8.