A preview containing scenes from an upcoming film is referred to as a "trailer" (currently they are shown before a feature in theaters but used to "trail" after them back in the '40s). Theatrical trailer is the one originally shown to promote the film; a "rerelease trailer" is one shown during a film's return engagement in theaters; and a "video trailer" has been designed to promote the film's release on home video. Some DVDs also include "TV spots," brief coming attractions designed to be shown as television commercials. Additional Trailers are bonus trailers of other movies, usually of the same genre or released by the same studio.