Tri"o (?), n. [It., fr. L. tres, tria, three: cf. F. trio, from the Italian. See Three.]
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.
2. Mus. (a)
A composition for three parts or three instruments.
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.