proscenium

proscenium, in theatre, the frame or arch separating the stage from the auditorium, through which the action of a play is viewed. In the ancient Greek theatre, the proscenium (Greek: proskēnion) originally referred to a row of colonnades, supporting a raised acting platform (logeion), and afterward to the entire acting area. A proscenium in the modern sense was first installed in a permanent theatre in 1618–19 at the Farnese Theatre built in Parma, Italy. It...