From The TV IV
DVD is an optical disc storage media format that is used for but not limited to storing movies with high video and sound quality. DVDs resemble compact discs: their physical dimensions are the same (12cm), but they are encoded in a different format and at a much higher density. It has been said that the acronym "DVD" doen't stand for anything, and is simply just three letters. For all intents and purposes however, most will say that "DVD" stands for Digital Video Disc or Digital Versatile Disc.