Window Parts and Features to Know

The window frame surrounds the entire window and consists of the head, jamb, and sill. Window frames are usually aluminum, vinyl, composite, or wood.

The head of the window is the top, horizontal part of the frame. It provides support so the full weight of the wall doesn't rest on the window.

The rail is the horizontal piece of a window sash where the frames of individual glass panes meet.

The jambs are the side, horizontal part of the frame and are located inside the framing. Components that open and close the window are located inside the jamb. Traditionally, the jamb matches the frame and trim.

The window casing is functional and decorative. It is the finishing trim piece of window installment and surrounds the frame to prevent drafts.

The window sash is the part of the window that opens and closes. It sits inside the frames and secures the glass in place.

Mutins are decorative dividers on window glass that can hold smaller panes of glass together or separate one larger pane of glass.

The sill is the bottom ledge of the window and can be referred to as the window stool. The exterior sill is important to keeping water out of the window by catching water and directing it away from the window and building.

The window apron is a decorative piece that goes beneath the window sill to create a look of finished molding.