ternary form

Basic musical form in three sections (ABA). A1 contains a musical statement in the tonic key and is complete in itself. B is usually in a new, but related, key and is a contrast to the music of A1. A2 is a restatement of the music of A1. An example of the ternary form is the minuet and trio. The 18th-century sonata form is a sophisticated ternary form with an extended middle (development) section. Ternary form can be recognized in popular music by the ‘middle-8’ or 8-bar middle section preceding the verse and chorus reprise.