Rondo Form Theory Things   William Wieland
Classical rondos alternate a tonic
refrain with contrasting episodes.

A = Refrain = Rondo = Rondo Theme

(other letters) = Episodes = Couplets

Transitions often link these sections.
A B A C A5-part Rondo or 2-couplet Rondo
A B A C A D A7-part Rondo
A B A C A B Aanother 7-part Rondo (an arch form or palindromic form)
A B A' C A'' D A'''Variation Rondo
A B A C B ATruncated Rondo
  A    B    A    C    A    B'  (A)
IV(Dev.)I
Sonata-rondo
Final movements of classical concertos are often in rondo form. The orchestra may present the initial refrain, repeated immediately by the soloist, or vice versa.
Fun examples: Leroy Anderson Sleigh Ride, John Williams Raiders March

Ritornello Form
The baroque ritornello form is similar to classical rondo form, but only the first and last refrains are in tonic. Examples include Handel Concerto Grossi.
RitornelloEpisodeRitornelloEpisodeRitornelloEpisodeRitornello
IV?I