Music Theory Resources
Ternary Form: A three-part form with the sectional thematic pattern ABA or ABA'. There are no repeat signs, and each section will be more or less self-contained. In this form, an initial section (A) is repeated at the end (either A or A'), after an intervening contrasting and fairly independent section (B). This middle section will be in a contrasting key (V, III, bVI, or something else). The form occurs in arias, slow movements of piano sonatas or symphonies, songs, etc., and may also be known as song form or aria.Although the B section is in a contrasting key, often the thematic material is related to that of the A section. Sometimes the same motives are used, or part of the A theme is restated in a different way, or motives from the A section may be developed. There are numerous possibilities.
The final A section is often altered for purposes of creating greater closure. A short coda (codetta) may be added for this purpose. In a song, there may be an extensive postlude in the piano for this purpose., but there may or may not be double bar lines separating the sections.
Typical schematic diagram: || A B A or A' || Major key: I V I or I III I or I bVI I or I ? I Minor key: i III i
Compound Ternary Form
In this form, each of the three sections of the ternary form exhibits an independent form such as a binary or rounded binary. A Minuet and Trio or Minuet and Schezo is an example of this form.