A-side and B-side

Use of this language has largely declined in the 21st century as the music industry has transitioned away from analog recordings towards digital formats without physical sides, such as downloads and streaming.

[2] Today, with the vast majority of music released and accessed digitally on streaming services, the traditional A-side/B-side is obsolete as a technological necessity.

Nonetheless, some contemporary artists have added on a second track to a single release as a nominal B-side, which can serve as an aesthetic choice as well as a promotional tool.

In the UK, the biggest-selling non-charity single of all time was a double A-side, Wings' 1977 release "Mull of Kintyre"/"Girls' School", which sold over two million copies.

However, some pop artists such as Prince, The Smiths, Def Leppard, Oasis, Bon Jovi and The Beatles have been particularly known for releasing strong material on B-sides.

A cassette tape showing the label for side A. The audio for side A is physically located on the opposite side since the tape head faces away from the label of its respective side.