Active Door
The door people use every time they enter or leave the house.

Astragal
The center member of a double door, which is attached to the fixed or inactive door panel.

Call Out Size (C.O.S.)
The nominal size of a window or door. In other words the “name” of the size. For instance, a window that is 3 feet wide and 4 feet high would have a call out size of 3040.

Casing
Molding or framing applied to the framework of doors and windows.

Cladding
A material, such as aluminum or vinyl, covering the exterior of a door or window, increasing durability with less maintenance.

Decorative Entry System
An entryway made up of a door in a frame, one or two sidelights, and a transom.

Door Frame
A group of wood parts machined and assembled to form an enclosure and support for a door; door frames are classified either as exterior or interior door frames.

Door Jamb
The part of a door frame that surrounds and contacts the edges of the stiles and the top rail of a door.

Flashing
A metal or plastic strip attached to the outside of the head or side jambs to provide a weather barrier, preventing leakage between the frame and the wall.

Frame
The area in which the window sash or door panels are mounted. Frame components include the head jamb, sill, side jambs and blind stop.

Glazing Stop
The part of the sash or door panel which holds the glass in place.

Head
The main horizontal member forming the top of the door frame.

Hinge
Two plates joined together by a pin and attached to a door and its frame whereby a door is supported and is enabled to swing or move.

Inactive Door
The door of a pair of doors that does not contain a lock, but is bolted when closed, and to which the strike is fastened to receive the latch or bolt of the active door.

Insulating glass (IG)
A combination of two or more panes of glass with a hermetically sealed air space between the panes of glass. This space may or may not be filled with an inert gas, such as argon.

Inswing
When the door opens into the house when opened.

Jambs
The wood that surrounds the door unit. The frame to which the door unit (door, doors, and/or doors and sidelights) is attached.

Kick Plate
A protective plate applied on the lower rail of the door to prevent the door from being marred.

Latch
A mechanism that holds a door shut; does not lock.

Light (also spelled lite)
Glazing framed by muntins and/or sash in a window or door.

Lock
A mechanism that holds a door shut and offers a locking option.

Low E Glass
A special glass type with a microscopically thin, metallic silver oxide bonded to one side of the glass that reduces heat transference, lowering home heating and cooling costs.

Outswing
When the door swings to the outside of the house when opened.

Panel
Usually refers to the separate panel or panels in a door frame

Rail
Term used for the horizontal pieces that constitute the top and bottom edges of a door.

Sidelight
Fixed panel of wood and glass next to door.

Stile
Term for the vertical pieces that constitute the side edges of a door.

Transom Bar
That part of a door frame that separates the top of a door or a window from the bottom of the transom.