trinitarian/ˌtɹɪn.ɪˈtɛə.ɹi.ən/EtymologyFrom French trinitaire (from Medieval Latin trinitarius, from Latin trinitas + -arius) + -ian.trinitarian means believing in the Trinity. Lexicurio rates it Rare gem — a strength score of 82 out of 100.adjBelieving in the Trinity.“It was no less than whether the psychic movement in Britain was destined to take a Unitarian or a Trinitarian course.”Of or pertaining to the Trinity (the three persons of the Godhead) or to the doctrine of Trinity.“The influence of trinitarian iconography is evident to varying degrees. Teresa and Elizabeth, for example, make reference to particular visual images of the Trinity.”Of or pertaining to a trinity, a group of three (almost exclusively when compared to the Christian Trinity).“In polytheism we find also a tendency to a trinitarian grouping of gods, and in each threefold group one god who was at least primus inter pares.”nounSomeone who believes in the Trinity, the three persons of the Godhead.A member of the Trinitarian order.