Synonyms for Triplet (same or very similar meaning)
WordNet sense 1 (the cardinal number that is the sum of one and one and one):
leash, ternary, three, trey, triad, trinity, trio, troika, deuce-ace, III, tercet, ternion, terzetto, tierce, trineWordNet sense 2 (a set of three similar things considered as a unit):
tripleFrom the ODE community, based on WordNetadd/edit