A small flat case with magnetic tape for audio or video

• Used to record and play back sound or pictures

Any similar small replaceable cartridge for a device

• For example, computer media or a cassette-type air conditioner unit

A lightproof container for photographic film

Molecular biology: a modular DNA sequence conferring a specific function

Bicycling: the cluster of sprockets on a freehub

To record audio or video onto a cassette