In music

Music

Music is an art form whose medium is sound and silence. Its common elements are pitch , rhythm , dynamics, and the sonic qualities of timbre and texture...

, the transition is the middle section

Section (music)

In music, a section is "a complete, but not independent musical idea". Types of sections include the introduction or intro, exposition, recapitulation, verse, chorus or refrain, conclusion, coda or outro, fadeout, bridge or interlude...

 or formal function, while the main theme

Theme (music)

In music, a theme is the material, usually a recognizable melody, upon which part or all of a composition is based.-Characteristics:A theme may be perceivable as a complete musical expression in itself, separate from the work in which it is found . In contrast to an idea or motif, a theme is...

 is the beginning, and the subordinate theme is the ending. It may traditionally be a part of the Sonata form

Sonata form

Sonata form is a large-scale musical structure used widely since the middle of the 18th century . While it is typically used in the first movement of multi-movement pieces, it is sometimes used in subsequent movements as well—particularly the final movement...

's exposition

Exposition (music)

In musical form and analysis, exposition is the initial presentation of the thematic material of a musical composition, movement, or section. The use of the term generally implies that the material will be developed or varied....

 in which the composer modulates

Modulation (music)

In music, modulation is most commonly the act or process of changing from one key to another. This may or may not be accompanied by a change in key signature. Modulations articulate or create the structure or form of many pieces, as well as add interest...

 from the key

Key (music)

In music theory, the term key is used in many different and sometimes contradictory ways. A common use is to speak of music as being "in" a specific key, such as in the key of C major or in the key of F-sharp. Sometimes the terms "major" or "minor" are appended, as in the key of A minor or in the...

 of the first subject to the key of the second, though many Classical era

Classical period (music)

The dates of the Classical Period in Western music are generally accepted as being between about 1750 and 1830. However, the term classical music is used colloquially to describe a variety of Western musical styles from the ninth century to the present, and especially from the sixteenth or...

 works move straight from first to second subject groups without any transition.

For example, transition may be defined as different from a subordinate theme (rondo form) or a developmental core

Musical development

In European classical music, musical development is a process by which a musical idea is communicated in the course of a composition. It refers to the transformation and restatement of initial material, and is often contrasted with musical variation, which is a slightly different means to the same...

.