Window & Door Glossary
Explore our glossary to understand essential terms related to window and door components and parts.
Terminology for Window Parts
Learn essential terms related to window components and their functions for informed decisions.
Understanding Door Components
Get familiar with door part terminology to enhance your knowledge and purchasing experience.
Glossary of Terms
Access definitions of key terms related to windows and doors for customer clarity.
Astragal
The exterior center post or moulding on a double door (attached to the secondary or inactive door panel)
Bay
Three connected windows (usually made up of a larger fixed window in the center and two smaller operating windows on either side) in a 30 degree or 45 degree angle formation
Awning
A single (or double) operating window in which the bottom of the sash swings outwards for ventilation
Bow
Four or more connected windows (fixed or operating) in a 10 degree or 15 degree angle formation
Brickmould
An exterior moulding around the window (to seal and cover the exposed window opening, insulation, interior jambs etc…)
Double Glazing
The interior decorative moulding/trim that covers the inside edge of the jambs and the rough openings between the window and the wall
Casing
The use of two panes of glass (in a window frame) to increase energy efficiency and to provide other performance benefits
Double Hung
A heavy beam extended across the top of the rough opening to help support the weight of the building
A bar used to visually separate glass into multiple lites (also named internal grid, muntin bar or window pane divider)
The glass panes in the sash of a window
A weatherstrip used to create a watertight seal between the sash and the window frame
Aluminum attached to the outside of the head or side jambs of a window to provide a weather barrier (preventing leakage between the frame and the wall)
Non-opening or non-operating window
A window large enough for exit in case of an emergency
An exterior aluminum moulding placed on the top of the brickmould or capping of a window frame
A window with two vertical operating sashes that slide up-and-down for ventilation
Flashing
Fixed
Egress Window
Drip Cap
Gasket
Glazing
Force exerted on a surface by moving air
A window or door that opens or operates
A watertight material used to prevent the passage of moisture through floors, walls and ceilings
A measure of heat transmission through a wall or window (the lower the U-Factor, the better the insulating value)
A window glazed with three panes of glass (enclosing two separate air spaces)
A smaller window attached above a door or another window
Wood installed vertically and horizontally to build a frame or wall
The amount of heat which has passed through the glass of windows and doors and has collected inside of the home
A window in which the top sash is fixed (or inoperable) and the bottom sash slides vertically up-and-down for ventilation
A method of constructing windows in which grills are attached to the inside and outside of glass panels to simulate the look of true divided lites
The row of bricks across the bottom of a rough opening
The horizontal part that forms the bottom of a window or door frame
Tall and narrow fixed glass on either (or both) sides of an entry door
Wooden wedges that are used to secure and level windows in the rough opening
A wooden board installed on the bottom contour of a bow or bay window (to provide a seat or shelf space)
A system of weights or coiled springs which assist in the raising and lowering of single hung and double hung window
The opening in a wall to accommodate the installation of a window or door
The horizontal parts of a window sash or door panel
The degree of the slope in a roof
A metal arm and gear which allows for easy opening or closing of projecting windows
A bar used to visually separate glass into multiple lites (also named internal grid, grill or window pane divider)
The connectors installed between individual windows in a multiple unit window
A commonly used term referring to a low emissivity coating placed on the glass surface to restrict the passage of radiant heat
Glazing framed by muntin bars and/or sash in a window or door
The moulding (or part of the window sash) which holds the glass in place
Glazing Stop
Wind Load
Venting Unit
Vapor Barrier
U-Factor
Triple Glazing
Transom
Stud
Solar Gain
Single Hung
Simulated Divided Lite
Sill Course
Sill
Sidelites
Shims
Seat
Sash Balance
Rough Opening
Rails
Pitch
Operator
Muntin
Mullion
Moulding
Low-E Glass
Lite
Header
Grill
A trim installed around the exterior perimeter of a window frame
