Transition (music)

In music, the transition is the middle section or formal function, while the main theme is the beginning, and the subordinate theme is the ending. It may traditionally be a part of the sonata form's exposition in which the composer modulates from the key of the first subject to the key of the second, though many Classical era 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.

In sonata form, a retransition is the last part of the development section which prepares for the return of the first subject group in the tonic, most often through a grand prolongation of the dominant seventh.