The 'Minuet and Trio' is a dance movement whose origins go back to the late Baroque. It appears, often as a last movement in suites of dances by Handel and J S Bach and many other contemporaries.
In the Classical period of Mozart and Haydn it almost always appears as the 3rd movement in a symphony, chamber or solo work. Minuets are in 3 time - eg: 3/4
The structure is as follows:
| Minuet | Trio | Minuet |
|---|---|---|
| AA - BB | CC - DD | AB |
Below is an audio clip of the Minuet and Trio from Mozart's last symphony, no 41 'Jupiter'
(English Baroque Soloists with John Eliot Gardiner - https://www.youtube.com/watch?v=yDAcHmU2mak)
Beethoven who was always pushing at the boundaries and had little time for the aristocracy, (who loved their ballroom dancing) replaced the Minuet with the Scherzo. (All the third movements of his symphonies are Scherzos even though some are labeled Minuet)
The Scherzo is a much faster, more vibrant and energetic version of the Minuet although it retains the structure of the Minuet and Trio.
Below is the Scherzo from Beethoven's 3rd Symphony 'Eroica'
(English Baroque Soloists with John Eliot Gardiner - https://www.youtube.com/watch?v=5XF4E4HYUd4)
Schumann often added a 2nd Trio section to his Scherzo ie: Scherzo - Trio 1 - Scherzo - Trio 2 - Scherzo.