1. (a.) Of or pertaining to the Trinity, the doctrine Of the Trinity, or believers in that doctrine.

2. (n.) One who believes in the doctrine of the Trinity.

3. (n.) One of a monastic order founded in Rome in 1198 by St. John of Matha, and an old French hermit, Felix of Valois, for the purpose of redeeming Christian captives from the Mohammedans.