a. [ Cf. F. trinitaire. See Trinity. ] Of or pertaining to the Trinity, the doctrine of the Trinity, or believers in that doctrine. [ 1913 Webster ]

n. 1. One who believes in the doctrine of the Trinity. [ 1913 Webster ]

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 Moslems. [ 1913 Webster ]

n. The doctrine of the Trinity; the doctrine that there are three distinct persons in the Godhead. [ 1913 Webster ]