In movie industry terminology usage, a sound track is an audio recording created or used in film production or post-production. Initially, the dialogue, sound effects, and music in a film each has its own separate track (dialogue track, sound effects track, and music track), and these are mixed together to make what is called the composite track, which is heard in the film. A dubbing track is often later created when films are dubbed into another language. This is also known as an M&E (music and effects) track. M&E tracks contain all sound elements minus dialogue, which is then supplied by the foreign distributor in the native language of its territory.
Current dictionary entries for soundtrack document soundtrack as a noun, and as verb. An early attempt at popularizing the term "sound track" was printed in the magazine Photoplay in 1929.A 1992 technical dictionary entry in Academic Press Dictionary of Science and Technology does not distinguish between the form sound track.