trío

Trío, from the Spanish and Italian word for "three," generally denotes a group of three individuals or things that perform, collaborate, or are considered together. In everyday language it can refer to any set of three items; in music and the performing arts, it is used for ensembles, works, or genres built around the number three.

The term derives from Latin tres through Romance languages, and in music it acquired a specialized sense by the 18th and 19th centuries to designate a composition for three players or a unit of three performers. Today, a trio can be instrumental, vocal, or mixed.

A piano trio traditionally comprises piano, violin, and cello, but many instrumental trios exist, including guitar trios and wind or string trios. A vocal trio is three singers who combine parts and harmony. In classical practice, "trio" can also refer to a standalone movement within a larger work or to the texture of a trio sonata, which historically involves three melodic lines often performed by four players with continuo.

In Latin American music, "trío" is a common label for vocal groups, notably the trío romántico and the trío huasteño, emphasizing harmonized singing with accompaniment. More broadly, "trío" appears in literature, film, and everyday speech to describe any collaboration or set of three related items.