Music
Music is used to create an atmosphere within a film or TV show. It can be used to signify key events or draw the audience's attention to certain actions (incidental music). It is mostly non-diegetic.
A soundtrack refers to songs which have been selected directly for the film.
A score is music which has been written specifically for the film or TV show.
Music can be used in a variety of ways, such as cueing suspense and signifying the emotions being evoked.
The choice of music usually comments on the narrative of a film.
Musical composers translate dramatic needs into musical terms; John Williams, Danny Elfman, Howard Shore, Hans Zimmer.
Contrapuntal Sound - sound that strongly contrasts with the mood or tone of the scene