triplet in WordNet English dictionary

1. the cardinal number that is the sum of one and one and one
   three  3  III  trio  threesome  tierce  leash  troika  triad  trine  trinity  ternary  ternion  triplet  tercet  terzetto  trey  deuce-ace 
   
2. a set of three similar things considered as a unit
   trio  triad  triplet  triple 
   
3. one of three offspring born at the same time from the same pregnancy
   triplet