Final answer:
The 'B' section in A-A-B-A form is known as the bridge. It contrasts with the 'A' sections, introducing new melodies or chords, and is not to be confused with the rhythm section, accompaniment, or chorus.
Step-by-step explanation:
In music, the A-A-B-A form is a common structure used in songwriting. The 'B' section of this form is known as the bridge. This part offers a contrast to the 'A' sections, which are typically the verse or theme of the song. The bridge provides a departure from the repetitive nature of the 'A' sections, introducing new melodies or chords and often leading into the final 'A' section with a sense of anticipation or completion.
It's important to note that the bridge is different from other elements of a song such as the rhythm section, which refers to the group of instruments establishing tempo and groove, and accompaniment, which is the musical backing for the main melody or vocal part. Additionally, the chorus is a separate, repetitive section intended to be the memorable and catchy part of the song, which is typically different from the bridge.