How does music function differently in opera and a stage play?

In the context of theatre, music functions differently in opera and a stage play based on its structural necessity and relationship to the narrative.

• In Opera: Music is the primary, governing element. It dictates the form of the dramatic imagery and dictates how the narrative develops. Because opera is a drama set to music in its entirety, the music is essential to the work's existence; it supports and intensifies the lyrics and action to create an emotional impact that neither element could achieve alone. In this medium, the music creates its own reality by sustaining a consistent convention of singing.12

• In a Stage Play: Music serves as an "equal partner" or a supporting element rather than the foundation. Known as incidental music, it is written to enhance a nonmusical medium by pointing up the mood or action, serving as a transition between scenes, or introducing and closing the performance. Unlike opera, where music is the primary driver, music in a stage play is used to intensify specific situations or feelings, and the drama can exist independently without it.13