This term is called the section of the musical form of the work, in which the thematic material is subjected to the most severe changes, that is being developed. This can be done in different ways: either by variation of the development previously heard themes, or with active motivic development, i.e. the crushing topics for small or minute segments, which are then subjected to various changes.
Meet the development, built on a new, previously unheard musical material.
The amount of development is arbitrary; it may consist of one or more episodes.
The main symptom development is tonal instability. Its function is to return to the main tonality of the work. Often the final section of the development is built on the so-called organ point or pedal - always resounding tone or chord is the dominant of the main key, which further increases the voltage, increases the anticipation of the main pitch, which will appear in the following development of the Reprise.
Actually, the term "development" refers to the middle section of the Sonata form, but the scenes development of the character may appear in the works of free-form, and Rondo-Sonata, and in three-part form, and in the Fugue.