Glossary - Windows and Doors

Glossary – Windows and Doors



Important terms you may need to know regarding windows and doors

Stars are a ranking system to indicate the energy efficiency of building products and materials that make up a
new home, from 0 to 5 stars. The more stars, the higher the energy rating. This is similar to star ratings that are produced on whitegoods.


An ornamental moulding fixed at the sides and tops of doors, windows and other openings. Its purpose is decorative and it also serves to cover the joints between the wall lining and adjacent woodwork. Awning window A window unit, hinged at the top, in which the bottom of the sash swings outward.


Bars (glazing bars)
Thin strips separating the pane or panes of glass in a sash.

Bay window
A composite of three windows, usually made up of a large centre unit and two side (or wing) units at a 45-degree
angle from the wall.

Bi-fold door
A door unit made up of two, three, four, five, six or seven panels hinged together to open in various configurations to create a large open expanse.

Bi-fold window
A window unit made up of two, three or four panels hinged together to open in various configurations to create a large open expanse.

Bow window
A composite of three or more window units in a radial or bow formation.

Brick opening
A planned opening in a brick wall into which window or door frames are built.

Building Code of Australia (BCA)
The Building Code of Australia outlines the standards, by law, which must be adhered to by the Australian building and construction industries.

Building envelope
The building envelope refers to the outer shell of the building, comprising all parts that create the separation between the interior and exterior, including walls, roof, floor, windows, doors.

Building fabric
The building fabric refers to the materials used to construct the building.


Casement window

A window unit, hinged at the side, in which the sash opens outwards like a door.

Chair rail
A fixed glazing rail or rigid push bar that provides protection from human impact.

Colonial bar
Applies to any short or light bar, either vertical or horizontal, used to separate glass in a sash into multiple lights.

A deviation from a straight line drawn side to side; a curvature across the face of the door.


Dead lock
A lock that can be actuated only by the key.

Dormer window
Upright window in a sloping roof. They provide headroom and better ventilation and light.

Double glazing
Glazing that incorporates two panels, separated with an air space, for the purpose of thermal and/or sound insulation.

Double-hung window
A window unit, with two sashes which by-pass each other vertically in the frame.


The glazed sash fitted over a door or window. Usually hinged like an awning window, it is designed for ventilation and light.

Federation bar
A style of glazing bar that forms a perimeter edging around a window or door sash.

Finger joint
A joint consisting of a series of fingers, precision-machined on the ends of two separate pieces of timber, which mesh and are firmly held together by an adhesive.

FirstRate is a software package that calculates the energy efficiency of the building products and materials that will make up a new home. The energy efficiency of these combined building products and materials result in a star energy rating — from 0 to 5 stars.

Fixed window
A non-openable window unit. A window unit with no moving parts. The glazing is usually fitted to the outer frame.

Any item that is used to secure members of a window assembly to each other, to secure an item of hardware to a window member or to secure a completed window assembly into the building structure.

Float glass
Glass manufactured by floating molten glass in a ribbon form on a heated liquid of greater density than the glass — usually molten tin.

Formed glass
Glass that has been heat treated to mould patterns or designs into the surface of the glass. Also known as slump glass.

The part of a window assembly surrounding the sashes or fixed glazing.

Frame (outer)
The top, sides and bottom that form a precise opening for the operating unit (the sash) of a window or door to function in.

Frame size
The overall external dimensions of a window or door frame.

French door
A particular design of swing door, all or a large part consisting of divided glass panes.


A hard, brittle, amorphous substance produced by fusion and usually consisting of mutually dissolved silica or silicates that also contain soda and lime. It may be transparent, translucent or opaque.

Glass bead
A moulding to secure glass in a window or door.

Fitting glass into a window or door.

Glazing bead
A plastic or timber strip applied to the sash around the perimeter of the glass on the outside face to hold the glass in place.


Generally, one of the botanical groups of trees that have broad leaves, in contrast to the conifers. The term has no reference to the actual hardness of the wood.

A transverse member forming the top of the window or door frame.

Hopper window
A window unit hinged at the bottom to usually open inward (but can also open outward) from the top.


The vertical side member of a frame. (see also Stiles)

A sash balance operating system used in a double-hung window.


Laminated glass
A composite material consisting of two or more sheets of glass permanently bonded together by a plastic interlayer material. Can be used to reduce noise transmission as well as increase security.

Glazing panels built up of small pieces of glass, usually of different colours, and to a pattern. The glass pieces are held in grooved lead strips called cames.

Light reflection
The percentage of light reflected by the exterior surface of the glass.

Light transmission
The percentage of external light that passes through the glass. The higher the percentage, the more daylight will enter the home.

A horizontal framing member placed across the top of the rough opening of a window or door opening to prevent the weight of the wall or roof from resting on the window frame.

A window or other construction that allows light into a room. Also denotes the sections into which a sash is subdivided by glazing bars.

LOSP stands for Light Organic Solvent Preservative. It is a chemical treatment used on timber to protect it from fungi, mould, termites and wood borers.

Low-E glass
Low emissivity (Low-E) glass has a coating that reflects radiant heat back into a room, or to the outside of a dwelling, depending on the glass orientation.

An opening with horizontal slats to permit passage of air and give reasonable weather protection. Available with timber, glass or metal slats.

Usually a fixed window between the operating window above and the floor level.


Masonry opening
The opening left in a masonry wall to receive a window or door unit.

Meeting rail
The bottom rail of the top sash and the top rail of the bottom sash of a doublehung window. In the closed position the two rails meet flush.

A slot or rectangular cavity cut into a piece of wood to receive another part.

Mortise and tenon joint
One in which a projection, machined on one piece, snugly fits into a rectangular-shaped, recessed opening machined in a second piece, and is secured under pressure with an adhesive. In a “through mortise” joint, the mortise and tenon extend through the full width of the material. In a “blind mortise”, the end of the tenon is not visible.

A vertical or upright member, between the head and the sill of a window, usually separating two panels.

Medium-density fibreboard is a strong, stable and easily decorated, manmade timber.


Covering at the top of a window to hide curtain fittings.

Picture window
A large non-operating window designed for maximum view without obstruction.

A finger-jointed, pre-primed, LOSP treated pine product with a high stress tolerance, suitable for window joinery.


Horizontal top and bottom members joining the stiles of a sash.

Room divider
A style of door. They use much less space and can be used to divide large rooms into discrete areas.

Rough opening
The opening left in a wall frame to receive a window or door unit. This is usually 20mm larger than the window or door frame dimensions.

Resistance to thermal transfer or heat flow. The higher the R-Value, the greater the insulating properties.


The separate, lighter frame to a window, carrying the glass. It may be fixed or moveable.

Sash cord
In double-hung windows, the rope or chain that attaches the sash to the counter balance.

Sash lift
A protruding handle screwed to the inside bottom rail of the lower sash on a double-hung window. In taller windows they may be fitted to the top rail of the lower sash, for ease of use.

Sash weighs
In older double-hung windows, the concealed weights that are used to counterbalance the sash.

Shading coefficient
Provides a measure of the energy transferred through the glass when exposed to sunlight compared to the energy transferred through 3mm clear glass. If cooling is paramount, the lower the number the better.

Side lights
See Side Panel.

Tall, narrow, fixed or operating sash on either or both sides of a door.

Side panel
A panel (operable or inoperable) located adjacent to a doorway. It may or may not be in the same plane as the doorway.

The bottom horizontal member of a window or door frame.

Sill course
The row of bricks, cement blocks or stones laid across the bottom of a masonry opening lying under the outside edge of the window sill.

Single glazing
Use of single panes of glass in a window.

Sliding window
A window unit with two or more sashes where one slides past the other, horizontally within the frame.

Generally, one of the botanical groups of trees that in most cases have needle or scale-like leaves; the conifers; also the wood produced by such trees. The term has no reference to the actual hardness of the wood.

Solar heat gain coefficient
The fraction of solar heat admitted through the glass directly transmitted, absorbed and subsequently released inwards expressed as a number between 0 and 1. If cooling
is paramount, the lower the number the better.

Solar reflection
The percentage of heat reflected by the exterior surface of the glass.

Solar transmission
The percentage of directly transmitted heat plus the absorbed and inwardly re-radiated heat that passes through the glass. If cooling is paramount, a lower solar transmission is better.

Sound transmission class (STC)
A rating for the efficiency of building materials and elements to reduce the transmission of sound. It is expressed in decibels (dB) and the larger the number the better the
reduction in noise passing through the material or element.

The upright or vertical frame pieces of a window sash or an opening door.

See Windmould.

Stud opening
The rough frame opening left in a timber frame wall to accept a designated window.


A rectangular projection cut out of a piece of wood for insertion into a mortise.

Textured glass
Textured glass incorporates textures and opaqueness within the glass to create privacy or design elements.

Toughened glass
Glass that has been strengthened and given modified fracture characteristics by heat treatment so the residual stresses are relatively high.

Toughened safety glass
Glass converted to a safety glass by subjection to a process of prestressing so that, if fractured, the entire piece disintegrates into small, relatively harmless particles.

A horizontal intermediate framing member.


The rate of heat loss or gain through the window from the warm side to the cold side. The lower the U-value, the better, especially in winter.

UV transmission
The percentage of ultraviolet light that passes through the glass. The lower the percentage, the better protection for furnishings and carpets from fading.


A material or device used to seal the openings, gaps or cracks of operable window and door units to prevent water and air penetration.

Wood (or metal) wedges used to secure the window or door unit in the rough opening in a plumb, level and square position during and after installation.

An external piece of timber, usually attached to the outside of a window, to suit different construction types (by increasing the “depth” of the frame.

Window Energy Rating Scheme (WERS)
A rating scheme that enables residential windows to be given a
star rating as a guide to their energy performance. The rating certifies the windows’ winter and summer efficiency as well as their ability to provide protection from fading. For each of these three categories, a number of stars from one to five is given. The more stars, the better the performance.

Window/door assembly
A complete unit comprising frame, couplings, sashes, glazing, infill panels and hardware.

Window light
A single panel or glazing in a windowassembly.

Window rating
The level of performance for strength and weatherproofness of windows and doors as determined by test. Window ratings are expressed in design wind pressure terms.

Information courtesy of Canterbury Windows and Doors and Stegbar (JELD-WEN)