ETYM Old Eng. thre, threo, thri, as. thrî, masc., threó, fem. and neut.
Being one more than two; SYN. 3, iii.
The cardinal number that is the sum of one and one and one; SYN. 3, III, trio, threesome, tierce, leash, troika, triad, trine, trinity, ternary, ternion, triplet, tercet, terzetto, trey, deuce-ace.