Mullion, Muntin, Stile and Jamb + Other Key Parts of a Window

If you are going to walk the walk, you should talk the talk.

Mullion, muntin, stile and jamb may sound a bit like a nursery rhyme but considering how much we like to “dress” them and the important contribution windows make to architectural beauty, it is important to know the names of the key window parts, don’t you think?

What are the parts of a window?

MULLION: a strip of wood or metal within, but not at either end, holding the panes of glass in a window. This term is synonymous with MUNTIN. The vertical piece on either end is called the STILE (see below)

JAMB : the vertical parts that form the outer sides of a window frame. This piece does not move up and down.

SASH: this is the part that moves up and down. It is the frame holding the panes of a window. Usually there is an upper sash and a lower sash. The vertical part of the sash is the STILE. The horizontal part of the sash is the RAIL.

Here is an excellent illustration showing window parts.