"33 RPM" refers to a speed at which vinyl records are played, specifically 33 and one-third revolutions per minute. This format was introduced by Columbia Records in 1948 and became the standard for long-playing (LP) records. The slower speed allows for more music to be stored on each side of the record, typically accommodating around 20-30 minutes of audio. The 33 RPM format is characterized by its larger diameter, usually 12 inches, which provides better sound quality compared to smaller records. Vinyl records at this speed are often used for albums, allowing artists to present a cohesive collection of songs in one package.