When measuring doors you'd say a 2/0 door for a 24" or 2' wide door. This measures the size of the door, not the opening. For windows, what would a 2/0 window be? The size of the sash or the size of the window as measured where? My wife is working with a client's builder and he said he'd put a 2/0 x 3/2 window in that space. My thought was this is a 2' wide window with 3 lights over 2 on both sashes. So the question is, where is the 2/0 measured at the brickmold, the sash or the window jamb? Or does the 3/2 mean it is 38" tall?