Lewis Short
trīmātus (noun M) : trimus
* The age of three years (post-Aug.): quae (gallinae) trimatum excesserunt,Col. 8, 5, 24: a trimatu,Plin. 8, 43, 68, § 168: in trimatu,id. 8, 50, 76, § 200; 10, 20, 22, § 44; Inscr. Orell. 4713.
Charlton T. Lewis, Charles Short, A Latin Dictionary