And the word 'cue' is used to denote one of these chunks of music to be written and performed in relation to one of the scenes or segments in the picture.
Composers usually make up the titles for each of their cues.
But its not unusual for that job to be left to the music editor. Traditionally, the code or number given to a cue is designed to reference that cue to the scene in the film to which it relates. The number of cues in a picture and the length of each cue can and do vary widely, of course, depending on the nature of the picture and the work habits and artistic inclinations of the composer, the music editor, the director, etc. If the film requires an exceptionally long, continuous run of music at some point, the composer will usually split it up into two or three 'cues', each to be separately recorded then spliced together later by the music editor. The total number of 'cues' or 'starts' must also be considered.