Sash Windows are a old type of windows where the glass panes are seperated by a narrow wooden bar, called a Sash. Sash windows, the term, is given primarily only to windows where the glazed panels can be opened by a vertical or sometimes horizontal sliding motion. Sash windows are more common in United Kingdom (especially England), but also found in some former colonies over such as in the United States.

The most common arrangement of sash windows has three panes across, and two panes up, thus giving an overall 3x4 pane window. Of course, every sash window is different, not all are the same.