noun, plural pro·sce·ni·a [proh-see-nee-uh, pruh-] /proʊˈsi ni ə, prə-/. Theater.
Examples from the Web for proscenium
The chief feat however is not yet performed, that which is to be acted in front of the Proscenium!Beethoven's Letters 1790-1826 Vol. 2|Lady Wallace
The Proscenium Arch is the arch or frame extending around the front of the stage of a theatre.The Boy Craftsman|A. Neely Hall
Anyway, I'm going to propose, him for the Stuyvesant and the Proscenium.The Younger Set|Robert W. Chambers