trinitarian

What it means

1. Someone who believes in the Trinity, the three persons of the Godhead.

   Antonyms: antitrinitarian, unitarian, Unitarian

2. A member of the Trinitarian order.

In a sentence

It was no less than whether the psychic movement in Britain was destined to take a Unitarian or a Trinitarian course.

1925 July – 1926 May, A[rthur] Conan Doyle, “(please specify the chapter number)”, in The Land of Mist (eBook no. 0601351h.html), Australia: Project Gutenberg Australia, published April 2019

Where it comes from

1. Latintrinitas
2. Frenchtrinitaire
3. EnglishTrinitarian

From French trinitaire (from Medieval Latin trinitarius, from Latin trinitas + -arius) + -ian.