triad

Noun

• a three-note major or minor chord; a note and its third and fifth tones

• three people considered as a unit

• a set of three similar things considered as a unit

• the cardinal number that is the sum of one and one and one

Related words

• Synonyms: 
  common chord , trio , threesome , trinity , triplet , triple , three , 3 , III , tierce , leash , troika , trine , ternary