A Digital Versatile Disc or Digital Video Disc is an optical disc storage media format. Its main uses are video and data storage. DVDs are of the same dimensions as compact discs (CDs), but store more than six times as much data. Variations of the term DVD often describe the way data is stored on the discs: DVD-ROM (Read Only Memory) has data that can only be read and not written; DVD-R and DVD+R can record data only once, and then function as a DVD-ROM; DVD-RW, DVD+RW, and DVD-RAM can both record and erase data multiple times.