Trinity

three in one, a trio. In theology, the unity of three persons, Father, Son, and Holy Spirit, in one Godhead. The doctrine of the trinity is a distinguishing tenet of the Greek, the Roman Catholic, and, if we except the Unitarian, nearly all Protestant churches. In recognition of the doctrine of the trinity, the number three is a favorite in Christian architecture. Three doorways or portals, three aisles, three-headed windows, the pattern of trefoil or three leaves in tracery, and many other similar uses of three have reference to the trinity. The three-petaled lily and the three-foliate clover leaf were for this reason favorite patterns in Christian ornamentation. See Arianism; Unitarianism; Nice