LP stands for "Long Play" and refers to a 12-inch vinyl record designed to rotate at 33⅓ revolutions per minute (RPM). Introduced by Columbia Records in 1948, the LP format revolutionized music by allowing an entire album's worth of material on a single disc — roughly 20-25 minutes per side, or 40-50 minutes total.
Before the LP, most records were 10-inch 78 RPM discs that held only about 3-4 minutes per side, limiting recordings to single songs. The LP's extended playing time enabled artists to create cohesive, long-form works — leading to the concept of the "album" as an artistic statement rather than just a collection of singles.
Today, "LP" is used interchangeably with "album" in vinyl collecting. When you see a record listed as an LP in a store or on Discogs, it means a standard full-length album on 12-inch vinyl at 33⅓ RPM. Double LPs (2xLP) spread the album across two discs for better sound quality, as wider groove spacing reduces inner groove distortion.
The first LP ever released was Mendelssohn's Violin Concerto in E Minor by the New York Philharmonic in 1948.