The frame members

The following diagram shows the parts of a window frame.

Diagram showing a window frame with the following parts labelled to indicate window frame terminology: head (the top of the frame), sill (the bottom), stile (the side of the frame), mullion (the central vertical timber), transom (the central horizontal timber), chair rail (a timber piece that sits below the transom), fixed pane (a window that does not open) and sash (the timber framework of the part of the window that opens).