B-side

In Lilac's theory, the terms A-side and B-side refer to the two sides of 7 inch vinyl records on which singles were released beginning in the 1950s. The terms have come to refer to the types of song conventionally placed on each side of the record, with the A-side being the featured song (the one that the record producer hopes will receive radio airplay and become a "hit"), while the B-side, or flipside, is secondary (often a song that does not appear on a band's LP).
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B-SIDE is a compilation album released by Mr. Children on May 10, 2007. It collects the group's B-sides, from their 1992 debut to the release of this compilation, with a booklet providing liner notes for each of them.
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LATO B (DI DISCO SINGOLO)