Acronyms that contain the term underscoring 

underscoring

Incidental music is music in a play, television program, radio program, video game, or some other presentation form that is not primarily musical. The term is less frequently applied to film music, with such music being referred to instead as the film score or soundtrack. Incidental music is often background music, and is intended to add atmosphere to the action. It may take the form of something as simple as a low, ominous tone suggesting an impending startling event or to enhance the depiction of a story-advancing sequence. It may also include pieces such as overtures, music played during scene changes, or at the end of an act, immediately preceding an interlude, as was customary with several nineteenth-century plays. It may also be required in plays that have musicians performing on-stage.

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