or Score, Soundtrack
Film music is known as a Film Score that is music specifically composed to accompany the film or selected from existing music, e.g. classical music or pop assembled to accompnay a motion picture. A film "soundtrack" is not the score, but refers to music used in the film and that is packaged and marketed in a co-promotion to the film. Music in a film can be both diegetic or nondiegetic or extradiegetic. Diegetic means it is part of the action of narrative the film. For eample, if a character in the film is playing a piano, or turns on a CD player, the resulting music is "diegetic." The score of a film is "non-diegetic" for the most part. It is also possible for diegetic and nondiegetic music to switch roles where the non-degetic music drifts into the film and vice versa (misic on film to film score / film scor that becomes music in the film).