ETYM Italian, from Latin tres, tria, three: cf. French trio, from the Italian. Related to Three.
1. A musical composition for three performers.
2. A set of three similar things considered as a unit; SYN. triad, triplet.
3. Three people considered as a unit; SYN. threesome, triad, trinity.
4. Three performers or singers who perform together.
In music, an ensemble of three instruments, also an interlude between repeats of a minuet or scherzo, for a trio of players.