trinity

From Old French trinité (French: trinité), from Latin trīnitās, from trīni (“three each”), from trēs (“three”).

trinity (plural trinities)

1. A group or set of three people or things; three things combined into one.
   • 1907, Robert William Chambers, chapter VIII, in The Younger Set, New York, N.Y.: D. Appleton & Company, OCLC 24962326:

     But when the moon rose and the breeze awakened, and the sedges stirred, and the cat's-paws raced across the moonlit ponds, and the far surf off Wonder Head intoned the hymn of the four winds, the trinity, earth and sky and water, became one thunderous symphony—a harmony of sound and colour silvered to a monochrome by the moon.

2. The state of being three; independence of three things; things divided into three.

• (group of three): threesome, triad, trio, trine, troika, triumvirate
• (independence of three): threeness

• nontrinitarian
• nontrinitarianism
• trinitarian

• Trinity
• Trinity College
• unity (oneness)
• duality (twoness)
• quaternity (fourness)
• quinity (fiveness)
• Unitarian