triad

名词 triad:

1. the cardinal number that is the sum of one and one and one
   同义词：three, 3, III, trio, threesome, tierce, leash, troika, trine, trinity, ternary, ternion, triplet, tercet, terzetto, trey, deuce-ace
2. a set of three similar things considered as a unit
   同义词：trio, triplet, triple
3. three people considered as a unit
   同义词：trio, threesome, trinity
4. a three-note major or minor chord; a note and its third and fifth tones
   同义词：common chord

1. A group or set of three; a triad.
   三个一组三个人或物组成的小组，三个一套