Frame: The outer structure of the window holding the sash in place.

Sash: The glass and the framing (stiles, rails) around the glass. For more on this, skip down to the next section.

Stiles: The vertical pieces of a sash.

Rails: The horizontal pieces of a sash.

Jamb: The pieces forming the top and sides of a window frame.

Stool: The horizontal piece jutting out at the bottom of a window frame — a favorite perch for cats everywhere.

Grilles: Bars applied to window glass to create a grid or other ornamental pattern. For more on this, skip down to window glass vocabulary.

Light (or lite): This term can have two meanings 1) A sheet of glass (also called a pane) in a window sash or door panel, and 2) an individual pane within a larger sheet of glass that’s created by grille bars.