A single-story structure located in front of the skene and protruding into the orchestra of a Classical theater. It was often faced with half-columns and was probably used as a raised stage. It was the frame or arch separating the stage from the auditorium, through which the action of a play was viewed. In the ancient Greek theater, the proscenium originally referred to a row of colonnades, supporting a raised acting platform (logeion), and afterward to the entire acting area.