filmwithinafilm
Film-within-a-film, also referred to as a metafilm or a film-within-a-film device, is a narrative technique in which a film or a portion of a film is presented inside another film. The inner film may be a diegetic work produced by characters, a movie being watched by characters, or a fictional project whose production is depicted on screen. The device is used to explore themes of representation, creativity, and the boundary between cinema and reality.
In practice, the inner film can appear as a separate in-universe text or as an on-screen work
Historical usage and significance: The film studio environment and self-referential humor have made the device a