noun
proscenium
pruh-SEE-nee-um/prəˈsiːniəm/
The front part of a theater stage, framed by an arch.
The actor steps onto the proscenium to address the audience.

Etymology
The components describe the space in front of the stage scenery. That spatial meaning developed into the theater area between the curtain and the orchestra, often including the curtain and its framework.
More examples
- Footlights illuminate the proscenium during the final scene.
- The dancers gather on the proscenium for their bows.
- From the balcony, we have a clear view of the proscenium.
Forms
proscenium · prosceniums · proscenia