Point to one of the circles in window. An explanation will appear in space. 

Insulating glass (IG): A combination of two or more
panes of glass with a hermetically sealed air space between them. This spaces may or may not be filled with an inert gas. IG with a special low emissions coating to restrict the flow of radiant heat is called Low-E insulating glass.

Cladding: A material secured to exterior or interior faces creating a more durable, low-maintenance surface.

Extension jambs: Flat wood parts which are fastened to the inside edges of the window jamb to extend it in width and adapt to a thicker wall. The inside edge of extension jambs should be flush with the finished wall surface; the inside casing is then secured to it.

Weatherstripping: Metal, plastic or felt strips
designed to seal between a window sash and frame or stops to prevent air and water leakage.

Frame: Outside member of window unit which encloses the sash, composed of side jambs, head jamb and sill.

Sash: The framework holding a glass in the window unit. Composed of stiles (sides) and rails (top and bottom).

Sash: The framework holding a glass in the window unit. Composed of stiles (sides) and rails (top and bottom).

Jambs: The window frame members which compose the top, sides and bottom (sill) of a unit.

Glazing: The glass panes or lights in the sash of a
window. Also the act of installing lights of glass in
a window sash.

Grille: Ornamental or simulated muntins and bars
which don't actually divide the lights of glass.
Generally made of plastic or wood, they fit on the
inside of the sash against the glass surface for easy removal. They can also be secured to the exterior of the sash.

Jambs: The window frame members which compose the top, sides and bottom (sill) of a unit.

Sill: Horizontal member that forms the bottom of a window frame.

Glazing: The glass panes or lights in a window sash or door panel. Also, the act of installing lights of glass in an opening

Stile: One of the upright members of the door panel or window sash, as at the outer edge of a door panel or a window sash.

Glazing stop: The part of the door panel which holds the glass in place.

Bottom rail: The lowest horizontal structural member of a door or window which interconnects the stiles.

Watershed: A horizontal sloping surface that diverts water away from the door panel or window sash.

Threshold: A strip fastened to the floor beneath a door, usually to cover the joint where two floor covers meet or to provide weather protection at exterior doors.

Fillet bead: Molding consisting of a narrow flat band; usually used in conjunction with or to separate other molding.

Side jamb: The frame member which compose the side of a unit.

Sill: Horizontal member that forms the bottom of a door frame

Drainage channel: The system that conveys water from the point of origin to a point of disposal.

Side jamb: The frame member which compose the side of a unit.

Trim set hardware: Decorative finish hardware, used either to operate functional hardware or to serve as functional hardware.

Lock stile: The vertical structural member of a door which closes against the jamb of the surrounding frame; the side away from the hinges.

Sill: Horizontal member that forms the bottom of a door frame.

Head jamb: The top frame member which compose the top of a unit.

Top rail: The top horizontal structural member of any piece of framing

Hinge: A device that allows the turning or pivoting of a part on a stationary frame.

Hinge stile: The vertical structural member of a door to which the hinges are fixed, and about which the door pivots.

Glazing: The glass panes or lights in a window sash or door panel. Also, the act of installing lights of glass in an opening

Side jamb: The frame member which compose the side of a unit.

Bottom rail: The lowest horizontal structural member of a door or window which interconnects the stiles.