sound recording on a narrow strip of a motion picture film
"The original soundtrack was scratched from the edge of the film reel before being transferred to magnetic tape."
A narrow strip running down a movie film that carries the recorded sound in synchronization with the pictures.
"The old projector's film got stuck, and without the intact soundtrack at the bottom of the reel, there was no audio to accompany the visuals."
In plain English: A soundtrack is all the music and sound effects played during a movie, TV show, or video game to set the mood.
"The movie's soundtrack features some of his most popular songs."
Usage: Use this word to refer specifically to the collection of musical pieces and audio effects accompanying a motion picture. It is often confused with "score," which technically denotes only the original instrumental composition written for the film rather than all recorded sounds.
To provide, or to act as the sound or music component of a film
"The composer spent years crafting an original soundtrack that perfectly matched the emotional arc of the movie."
In plain English: To soundtrack something means to add music that matches what is happening on screen or stage.
"The old movie soundtrack begins to play softly in my memory every time I hear that melody."
The word soundtrack is a straightforward combination of sound and track. It was first used to describe the audio recorded on a film reel that runs alongside the picture.