1. (noun)three, 3, III, trio, threesome, tierce, leash, troika, triad, trine, trinity, ternary, ternion, triplet, tercet, terzetto, trey, deuce-ace the cardinalnumber that is the sum of one and one and one
2. (noun)trio, triad, triplet, triple a set of three similar things considered as a unit
3. (noun)trio, threesome, triad, trinity threepeople considered as a unit
4. (noun)common chord, triad a three-note major or minor chord; a note and its third and fifth tones