Musical development in the context of Hoboken-Verzeichnis

In music, a section is a complete, but not independent, musical idea. Types of sections include the introduction or intro, exposition, development, recapitulation, verse, chorus or refrain, conclusion, coda or outro, fadeout, bridge or interlude. In sectional forms such as binary, the larger unit (form) is built from various smaller clear-cut units (sections) in combination, analogous to stanzas in poetry or somewhat like stacking Lego.

Some well known songs consist of only one or two sections, for example "Jingle Bells" commonly contains verses ("Dashing through the snow...") and choruses ("Oh, jingle bells..."). It may contain "auxiliary members" such as an introduction and/or outro, especially when accompanied by instruments (the piano starts and then: "Dashing...").

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 sonata form, the exposition is "the first major section, incorporating at least one important modulation to the dominant or other secondary key and presenting the principal thematic material."
• In a fugue, the exposition is "the statement of the subject in imitation by the several voices; especially the first such statement, with which the fugue begins."

In music theory, the recapitulation is one of the sections of a movement written in sonata form. The recapitulation occurs after the movement's development section, and typically presents once more the musical themes from the movement's exposition. This material is most often recapitulated in the tonic key of the movement, in such a way that it reaffirms that key as the movement's home key.

In some sonata form movements, the recapitulation presents a straightforward image of the movement's exposition. However, many sonata form movements, even early examples, depart from this simple procedure. Devices used by composers include incorporating a secondary development section, or varying the character of the original material, or rearranging its order, or adding new material, or omitting material altogether, or overlaying material that was kept separate in the exposition.

The 1957 Encyclopédie Larousse defines a cell in music as a "small rhythmic and melodic design that can be isolated, or can make up one part of a thematic context". The cell may be distinguished from the figure or motif:the 1958 Encyclopédie Fasquelle defines a cell as "the smallest indivisible unit", unlike the motif, which may be divisible into more than one cell. "A cell can be developed, independent of its context, as a melodic fragment, it can be used as a developmental motif. It can be the source for the whole structure of the work; in that case it is called a generative cell."

A rhythmic cell is a cell without melodic connotations. It may be entirely percussive or applied to different melodic segments.

In musical composition, developing variation is a formal technique in which the variations are produced through the development of existing material. The term was coined by Arnold Schoenberg, twentieth-century composer and inventor of the twelve-tone technique, who believed it was one of the most important compositional principles since around 1750:

The technique has also become associated with Johannes Brahms, whom Schoenberg believed to have used it in its "most advanced state".

Process music is music that arises from a process. It may make that process audible to the listener, or the process may be concealed.

Primarily begun in the 1960s, diverse composers have employed divergent methods and styles of process. "A 'musical process' as Christensen defines it is a highly complex dynamic phenomenon involving audible structures that evolve in the course of the musical performance ... 2nd order audible developments, i.e., audible developments within audible developments". These processes may involve specific systems of choosing and arranging notes through pitch and time, often involving a long term change with a limited amount of musical material, or transformations of musical events that are already relatively complex in themselves.

Binary form is a musical form in 2 related sections, both of which are usually repeated. Binary is also a structure used to choreograph dance. In music this is usually performed as A-A-B-B.

Binary form was popular during the Baroque period, often used to structure movements of keyboard sonatas. It was also used for short, one-movement works. Around the middle of the 18th century, the form largely fell from use as the principal design of entire movements as sonata form and organic development gained prominence. When it is found in later works, it usually takes the form of the theme in a set of variations, or the Minuet, Scherzo, or Trio sections of a "minuet and trio" or "scherzo and trio" movement in a sonata, symphony, etc. Many larger forms incorporate binary structures, and many more complicated forms (such as the 18th-century sonata form) share certain characteristics with binary form.

A secondary development, in music, is a section that appears in certain musical movements written in sonata form. The secondary development resembles a development section in its musical texture, but is shorter and occurs as a kind of excursion within the recapitulation section.

Charles Rosen, who has written extensively on the concept, presents the idea as follows: