soundtrack

/S AW1 N D T R AE0 K/
noun
  1. 1

    A narrow strip running down a movie film that carries the recorded sound in synchronization with the pictures.

  2. 2

    The sound (especially the music) component of a movie, video game, etc.

  3. 3

    A recording of such music for sale.

  4. 4

    Background sounds that are part of a bigger event.

verb
  1. 1

    To provide, or to act as the sound or music component of a film

Source: https://en.wiktionary.org/wiki/soundtrack