Definition of "cassette"

A small flat case containing magnetic tape on two reels, used to record and play back audio and video material.  quotations  examples

Any similar small cartridge, such as for a computer disk or cassette air conditioner  examples

(photography) A lightproof container for photographic film.  examples

(genetics) A modular DNA sequence encoding one or more genes for a single biochemical function.  examples

(cycling) A set of sprockets mounted onto a splined shaft on the freehub.  examples

A saggar (ceramic container used in a kiln)  examples