A sash window or hung sash window is made of one or more movable panels, or "sashes". The individual sashes are traditionally paned windows, but can now contain an individual sheet of glass.

What do window sashes do?

A window sash is the part of a window that moves and holds the glass panes together. The sash fits inside the window frame, which is attached to the house. The sash will vary slightly depending on the type of window. ... Having two sash makes the double hung window the easiest window style to operate and clean.

Does a window sash include the glass?

The sash is the name given to the frame that contains the glass, and there will usually be a top and a bottom sash in a typical window. If we are going to be specific, the full title of a sash window is a 'vertical double-hung box-framed sliding sash window'!