in audio and video recording, flat, rectangular container made of plastic or lightweight metal that holds magnetic tape for audio or video recording and replay. A tape cassette is designed so that it can be inserted in a recorder and used immediately; it eliminates the need to thread a portion of the tape manually before starting the recorder. In a cassette the tape begins on a feed reel at one side and moves along guides through the record-playback mechanism, after which it passes on to the take-up reel on the opposite side.

Audiocassette tape is only 0.15 inch (3.8 millimetres) wide but can carry four to eight tracks. Videocassette (videocassette recorder) tape used in home video recorders is ¹/₂ inch (12.7 millimetres) wide; the type employed by television broadcasters measures 2 inches (5 centimetres) in width.

Audiocassettes, which were introduced for home use in the 1960s, may be provided with prerecorded materials or with blank tape so that users can record whatever they wish. Videocassettes, which became available to consumers in the early 1970s, may also contain prerecorded materials, such as reproductions of popular motion pictures, or blank tape for recording television programs and for producing home movies. A lightproof magazine for photographic film or plates is also styled a cassette.