Sections of songs are usually broken up by the musical themes running through the song, or even what key a particular section of a song is based in. The structure of the song is denoted by letters, and every time a new section is written, and if it sounds different (or if the chord structure is different) than prior sections, then it is assigned a new letter.
Originally, there were sections of the song ABACAB named A, B, and C. So, there would be a section A, then B, then A was repeated, then a new section named C, came, then sections A and B were repeated, closing the song. Down the line, the original song was re-worked, and the structure no longer followed that original order (ABACAB), but they liked the name so they kept it and incorporated it into the chorus.
Sections of songs are usually broken up by the musical themes running through the song, or even what key a particular section of a song is based in. The structure of the song is denoted by letters, and every time a new section is written, and if it sounds different (or if the chord structure is different) than prior sections, then it is assigned a new letter.
Originally, there were sections of the song ABACAB named A, B, and C. So, there would be a section A, then B, then A was repeated, then a new section named C, came, then sections A and B were repeated, closing the song. Down the line, the original song was re-worked, and the structure no longer followed that original order (ABACAB), but they liked the name so they kept it and incorporated it into the chorus.