The A-side and B-side are the two sides of phonograph records and cassettes; these terms have often been printed on the labels of two-sided music recordings.

What does B-side mean?

It's a term for the song on the other side of a single that's usually not included in the album. It's become a more broad term now with vinyl singles not being as common and people will call any song not released on an album a B side.

What is considered AB side?

The A-side and B-side are the two sides of phonograph records and cassettes, and the terms have often been printed on the labels of two-sided music recordings. ... The term B-side carries a more expansive definition in the K-pop industry, referring to all tracks on an album that are not marketed as title tracks.