\Trin`i*ta"ri*an\, a. [Cf. F. trinitaire. See {Trinity}.] Of or pertaining to the Trinity, the doctrine of the Trinity, or believers in that doctrine.
\Trin`i*ta"ri*an\, n. 1. One who believes in the doctrine of the Trinity. 2. (Eccl. Hist.) 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.