trio Meaning, Definition & Usage

  1. noun the cardinal number that is the sum of one and one and one
    deuce-ace; triplet; tercet; tierce; troika; three; trey; 3; ternion; trine; ternary; triad; threesome; leash; III; trinity; terzetto.
  2. noun a musical composition for three performers
  3. noun three performers or singers who perform together
  4. noun a set of three similar things considered as a unit
    triad; triplet; triple.
  5. noun three people considered as a unit
    threesome; trinity; triad.

WordNet

Tri"o noun
Etymology
It., fr. L. tres, tria, three: cf. F. trio, from the Italian. See Three.
Definitions
  1. Three, considered collectively; three in company or acting together; a set of three; three united.
    The trio were well accustomed to act together, and were linked to each other by ties of mutual interest. Dickens.
  2. (Mus.) (a) A composition for three parts or three instruments. (b) The secondary, or episodical, movement of a minuet or scherzo, as in a sonata or symphony, or of a march, or of various dance forms; -- not limited to three parts or instruments.

Webster 1913