Head – The top horizontal section of the window frame.

Frame – The exterior structure that supports the entire window.

Grids – Exterior or interior strips of window frame material that simulate a divided piece of glass.

Hardware – The window locks and/or operating handles.

Insulated Glass (IG) – A combination of two or more panes of glass separated by spacer material.

Jamb – The vertical sides of a window frame.

Rail – A rail is the horizontal section of the “Sash” (see Sash explanation below). There is an upper and lower rail.

Sash – The sash is the material that surrounds the glass and holds it in place. It can be fixed or operable. The top piece is the “Upper Sash” and the bottom piece is the “Lower Sash.”

Sill – The horizontal section (ledge) that forms the bottom of the window frame.

Weather-stripping – A piece of material that helps fill the gaps between moving and stationary parts of the window. The strip is found between the sash and the frame.