Rondo

Rondo, and its French equivalent rondeau, is a word that has been used in music in a number of ways, most often in reference to a musical form, but also in reference to a character-type that is distinct from the form. Although now called rondo form, the form started off in the baroque period as the ritornello form, coming from the latin word ritornare meaning "to return", indicating the return to the original theme or motif ("A"). Although consisting of a few differences, some people use the two terms interchangeably. See the following address to see the differences. Rondo and Ritornello Forms in Tonal Music

In rondo form, a principal theme (sometimes called the "refrain") alternates with one or more contrasting themes, generally called "episodes," but also occasionally referred to as "digressions," "couplets," or "subordinate themes." The overall form can be represented as ABACADA ... The number of themes can vary from piece to piece, and the recurring element is sometimes embellished or shortened in order to provide for variation.

The form began to be commonly used from the classical music era, though it can be found in earlier works. In the classical and romantic periods it was often used for the last movement of a sonata, symphony, concerto or piece of chamber music.

Rondo was often used by baroque composers to write Ritornello rondos. They were used in the fast movements of baroque concertos and contrast the whole orchestra (who play the main theme) against soloists (who play the episodes.) But Ritornello does differ slightly from other Rondos in that the theme is often different when it recurs but is always distinguishable as the same theme.

Classical pieces often end with a rondo. The fourth movement of a piece is often a rondo. Concertos and sonatas, however, have the third movement as a rondo.

A common expansion of rondo form is to combine it with sonata form, to create the sonata rondo form. Here, the second theme acts in a similar way to the second theme group in sonata form by appearing first in a key other than the tonic and later being repeated in the tonic key. Unlike sonata form, thematic development does not need to occur except possibly in the coda.

Rondo as a character-type (as distinct from the form) equates to music that is fast and vivacious—normally allegro. Music that has been designated as "rondo" normally subscribes to both the form and character. On the other hand, there are many examples of slow and reflective works that are rondo in form but not in character. Composers normally do not identify such works as "rondo".