a cardinal number, 2 plus 1.

a symbol for this number, as 3 or III.

a set of this many persons or things.

a playing card, die face, or half of a domino face with three pips.

amounting to three in number. ?

three sheets in the wind. sheet 2 ( def. 3 ) .

noun

threesome , triad , trine , trinity , triple , triumvirate , triune , triunity , troika , menage a trois , ternary , ternion , third , trichotomy , trilogy , trio , tripartition , triplet , triplets , triplex , triplicate , triplication , triplicity , trivium

adjective

pyramidal , ternary , ternate , third , treble , triangular , trichotomic , trichotomous , trigonal , trigonous , trilateral , trinal , trinary , trinitarian , tripartite , triple

verb

triplicate , trisect