Minuet and Trio form has a special type of compound temary design (in which
each of the sections has its own small form):
Minuet (an aristocratic dance in 3/4 meter)
This section usually has a strong downbeat, and has a binary design
in which each sub-section is repeated.
Trio (the texture is usually reduced to three structural lines)
The "Trio" is noticeably lighter and sweeter than the Minuet.
(As in the Minuet, each sub-section is repeated).
Minuet (returns without repeats)
Before 1800, Minuet and Trio was the traditional form used in third movements
of 4-movement Classic instrumental works.
Scherzo & Trio Form
After 1800, Beethoven and other politically-minded composers replaced the
aristocratic "Minuet" with a heavier "folk-derived" dance in 6/8 meter called a
scherzo (which means "a common joke" in Italian), creating a similar design
called Scherzo and Trio form (the standard 3rd movement form of the late