ETYM Latin trias, -adis, Greek tri- three: cf. French triade. Related to Three, Trias, Trio.
1. A union of three; three objects treated as one; a ternary; a trinity.
2. A chord of three notes; the common chord, consisting of a tone with its third and fifth, with or without the octave.
3. An element or radical whose valence is three.
4. Group of three; Music, chord of three notes.
1. Groupe de trois.
2. Mafia chinoise.