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.