Optical disc
Flat, usually circular disc that encodes binary data / From Wikipedia, the free encyclopedia
This article is about digital storage media such as CDs and DVDs. For a similarly-named anatomic feature of the eye, see optic disc.
"Optical media" redirects here. For transmission media for light, see Optical medium. For broader definition, see optical storage.
An optical disc is a flat, usually[note 1] disc-shaped object that stores information in the form of physical variations on its surface that can be read with the aid of a beam of light. Optical discs can be reflective, where the light source and detector are on the same side of the disc, or transmissive, where light shines through the disc to be detected on the other side.
Optical discs can store analog information (e.g. Laserdisc), digital information (e.g. DVD), or store both on the same disc (e.g. CD Video).
Their main uses are the distribution of media and data, and long-term archival.