Minuet
Composers liked the music of the minuet and often wrote them just as pieces of music for a keyboard or other instruments.  Composers like Bach and Handel included them in their suites (collection of dance movements).  Lully started to put them in his operas, often in pairs: Minuet I, Minuet II, then Minuet I repeated.  Often the second minuet would be played by three instruments, so it was called a trio.