A-side and B-side

The A-side and B-side are the two sides of vinyl records and cassettes, and the terms have often been printed on the labels of two-sided music recordings, which in purely technical terms of recording and playback do not favor any side over the other. The A-side of a single usually features a recording that its artist, producer, or record company intends to be the initial focus of promotional efforts and radio airplay, with the aim of it becoming a hit record. The B-side (or "flip-side") is a secondary recording that typically receives less attention, although some B-sides have been as successful as, or more so than, their A-sides.