At the beginning of the 20th century, a pattern of composing music gained popularity in U.S. pop music that was adopted from classical music. A piece consisted of two parts, A and B, each commonly consisting of 8 measures. At first, A was played twice (but with different verses); then the B part, thereafter once more the A part (together 32 measures, therefore also called thirty two bar form). At the end, a coda could follow.

The repeating A part is called chorus, the B part bridge.

The archetype of this form was the German Meistersang, whose repeating bar form in the sequence of stanza (A) – counter-stanza (A) – aftersong or bridge (B) – reprise (A) corresponds exactly to this pattern.

This pattern belongs to the group of ternary forms.