A cassette is a small plastic case containing magnetic tape used for recording and playing music or other sounds. Before digital music, people listened to cassettes in portable players called Walkman devices, in car stereos, and in home systems. You could buy pre-recorded cassettes with albums by your favorite artists, or record your own music onto blank cassettes to create custom mixtapes for friends.

Inside each cassette, thin brown tape winds between two small wheels called spools. When you press play, the tape moves past a magnetic head that reads the recorded sounds, similar to how a record player's needle reads grooves in vinyl. You could rewind or fast-forward through songs, though finding exactly the right spot often required patience and practice.

Cassettes were hugely popular from the 1970s through the 1990s. They were more portable and durable than vinyl records, and you could record over them repeatedly. Many people still have boxes of old cassettes in their attics. While CDs and then digital music eventually replaced cassettes, some musicians today release cassette versions of their albums as nostalgic collectors' items.

The word also appears in video cassette, which worked the same way but recorded images and sound for movies and TV shows.