What is in a drawing, picture, etc., that part of the surface, as of paper or canvas, which is within the frame or the border or margin. In a frame or the like, the open space, the opening called?

sight — In a drawing, picture, etc., that part of the surface, as of paper or canvas, which is within the frame or the border or margin. In a frame or the like, the open space, the opening. (Webster's 1913.)