Rigid circular plate of either metal or plastic used to record video and audio signals for playback. It resembles a phonograph record and can be played on a machine attached to a conventional television receiver. There are two major classes of videodiscs, magnetic and nonmagnetic. Magnetic videodiscs have an oxide-coated surface onto which input signals are recorded as magnetic patterns in spiral tracks. Nonmagnetic videodiscs use either a mechanical recording system analogous to that used in phonograph records, or optical technology that uses a laser to read data coded as a sequence of pits on the disc. The most common type of videodisc today is the DVD.

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Person who plays recorded music on radio or television or at a nightclub or other live venue. Disc jockey programs became the economic base of many radio stations in the U.S. after World War II. The format generally involves one person, the disc jockey, introducing and playing phonograph records and chatting informally, usually extemporaneously, in the intervals. Because popular DJs are in a position to influence public tastes, record companies have sometimes attempted to bribe them with money and gifts, known as “payola.”

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Molded plastic disc containing digital data that is scanned by a laser beam for the reproduction of recorded sound or other information. Since its commercial introduction in 1982, the audio CD has become the dominant format for high-fidelity recorded music. Digital audio data can be converted to analog form to reproduce the original audio signal (see digital-to-analog conversion). Coinvented by Philips Electronics and Sony Corp. in 1980, the compact disc has expanded beyond audio recordings into other storage-and-distribution uses, notably for computers (CD-ROM) and entertainment systems (videodisc and DVD). An audio CD can store just over an hour of music. A CD-ROM can contain up to 680 megabytes of computer data. A DVD, the same size as traditional CDs, is able to store up to 17 gigabytes of data, such as high-definition digital video files.

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Data storage

• Aluminum disc, a magnetic recording disc used mainly for early radio recordings
• Blu-ray Disc, a high-density optical disc intended mainly for video storage
• Compact Disc, a form of optical disc used mainly for audio data
• Disc film, a still-photography film format
• Disk storage, a general category of data storage mechanisms
• DVD, a form of optical disc used mainly for video and other data
• Enhanced Versatile Disc, an optical medium-based digital audio/video format under development (shortform EVD)
• Floppy disk, a magnetic data storage device using a flexible disc
• Hard disk drive, a non-volatile magnetic data storage device
• HD DVD, a high-density optical disc intended mainly for video storage
• Laserdisc, the first commercial optical disc storage medium
• MiniDisc, a magneto-optical disc-based data storage device
• Optical disc, a polycarbonate disc
• RAM disk, a volatile solid state drive
• Transcription disc, a gramophone record
• A generic name for secondary storage in a computer

Science

• Accretion disk, diffuse material in orbital motion around a central body such as a star or black hole
• Death Inducing Signaling Complex, in biology, a multi-protein complex formed by members of the death receptor family of apoptosis-inducing cellular receptors
• Debris disk, a ring shaped circumstellar disk of dust and debris in orbit around a star
• DISC1 (Disrupted in Schizophrenia 1), a human gene with a wide array of interactions
• DISC assessment, in psychology, a group of psychometric tests based on the work of William Moulton Marston
• Disc (galaxy), a disc-shaped group of stars
• Disk (mathematics), the region in a plane surrounded by a circle
• Intervertebral disc, in biology, part of the spine of an animal
• Protoplanetary disk, a rotating disc of dense gas surrounding a newly formed star, a form of accretion disc
• Scattered disc, a distant region of the Solar System thinly populated by icy minor planets
• Unit disk, a disc (mathematics) with radius one

Motoring

• Disc brake, a device for slowing or stopping the rotation of a wheel
• Disc parking, a parking regulation with free parking when using a parking disc (clock disc)
• Tax disc, a vehicle licence receipt placed inside the windscreen in the United Kingdom

Other uses

• DİSK, the Confederation of Revolutionary Trade Unions of Turkey
• Disc jockey, a person who selects and plays pre-recorded music for an audience
• Flying disc, a throwing toy or Frisbee
• Dundee International Sports Centre, a sports centre in Scotland
• Defence Intelligence and Security Centre, headquarters of the British Army Intelligence Corps
• Delaware Independent School Conference, a high-school sports conference

See also

• Spelling of disc