1. a three-note major or minor chord
a note and its third and fifth tones

Synonym: common chord

2. three people considered as a unit

Synonym: triothreesometrinity

3. a set of three similar things considered as a unit

Synonym: triotriplettriple

4. the cardinal number that is the sum of one and one and one

Synonym: three3IIItriothreesometierceleashtroikatrinetrinityternaryterniontriplettercetterzettotreydeuce-ace