1. Frame The combination of head, jambs and sill to form a precise opening in which a window sash or door panel fits.   2. Glass A framed sheet of glass within a window or door frame.   3. Grilles Any bar that divides window or door glass. Also called a muntin, grid or windowpane divider.   4. Head The main horizontal part forming the top of the window or door frame.   5. Jamb The main vertical parts forming the sides of a window or door frame.   6. Sash A single assembly of stiles and rails made into a frame for holding glass.   7. Sill The main horizontal part forming the bottom of the frame of a window or door.