Webster’s Revised Unabridged Dictionary · 1913 Trinal Tri′nal (trī′nal), a. [L. trinus triple, trini three each, fr. tres, tria, three. See Three, and cf. Trine, a. & n., Tern, a.] Threefold. "Trinal unity." Milton. In their trinal triplicities on high. Spenser. ‹ Trimyarian Trindle ›