Definify.com
Webster 1913 Edition
Trio
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 1828 Edition
Trio
TRI'O
,Noun.