[1] : WordNet (r) 2.0

threesome
     n 1: the cardinal number that is the sum of one and one and one
          syn: three, 3, iii, trio, tierce, leash, troika,
           triad, trine, trinity, ternary, ternion, triplet,
           tercet, terzetto, trey, deuce-ace
     2: three people considered as a unit syn: trio, triad, trinity
see also:
three 3 iii trio tierce leash 
troika triad trine trinity ternary 
ternion triplet tercet terzetto trey 
deuce-ace 

[2] : Moby Thesaurus II by Grady Ward, 1.0

63 moby thesaurus words for "threesome":
   bout, clover, contest, decathlon, deuce-ace, double-header,
   doubles, event, foursome, game, games of chance, go, leash, match,
   meet, pentathlon, play, play-off, race, runoff, set of three,
   shamrock, singles, sport, tercet, ternary, ternion, terzetto,
   three, tierce, trefoil, trey, triad, trialogue, triangle, tricorn,
   trident, triennium, trihedron, trilogy, trimester, trine, trinity,
   trinomial, trio, triphthong, triple, triple crown, triple threat,
   triplet, triplopy, tripod, triptych, trireme, triseme, triskelion,
   trisul, triumvirate, triune, triunity, trivet, troika, twosome

Threesome >> T Words
Threesome, definition of term: Threesome
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