IPA: /prəˈsiːniəm/
KK: /prəˈsiːniəm/
The part of a theater stage that is in front of the curtain, often framed by an arch, where the audience can see the performance.
The actors took their positions on the proscenium stage, ready to begin the play.
Proscenium → It is formed from "pro-" (meaning before or in front of) and "scena" (meaning stage or scene). The word refers to the part of a theater stage that is in front of the curtain, literally meaning the area before the stage.
Think of the 'front' ('pro-') of the 'stage' ('scena') when you remember that proscenium refers to the area in front of the stage.