Videotape is magnetic tape used for storing video and usually sound in addition. Information stored can be in the form of either an analog signal or digital signal. Videotape is used in both video tape recorders (VTRs) or, more commonly, videocassette recorders (VCRs) and camcorders. Videotapes are also used for storing scientific or medical data, such as the data produced by an electrocardiogram.
Because video signals have a very high bandwidth, and stationary heads would require extremely high tape speeds, in most cases, a helical-scan video head rotates against the moving tape to record the data in two dimensions.
Info gleaned from Wikipedia