The scientific study of sound especially its generation, transmission and reception.

Air Gap
Air space between the panes of glass in an insulating glass unit (IGU).

Air Infiltration
Term used to describe one of the tests required by AS2047. The window shall not exceed air leakage requirements as specified for either air conditioned buildings or non-air conditioned buildings.

Annealed Glass
Glass which is cooled gradually during manufacture in an annealing operation to reduce residual stresses and strains which can be produced during cooling. This is the ordinary glass used in windows.

Arched Head
A curved and glazed portion of the window located at the head of the window.

An inert, non-toxic gas used in insulating windows to reduce heat transfer.


A moulding or stop used to hold glass or panels in position. It can be aluminium, timber, rigid PVC or flexible PVC.

Bottom Rail
The bottom horizontal sash bar.

Brick Opening
Opening size measured between the outside brick faces.

Brick Veneer
Construction where the outside skin of the wall is brickwork and the inside wall is timber stud frame.

The window frame is installed as the building progresses. Window fitted into the wall as the wall is being built.

Butt-Joined Glazing
Installation of glass products where the vertical glass edges are without structural supporting mullions.


The space between the panes of glass in an insulating glass unit (See also Air Gap).

Cavity Brick
A type of construction where both the outside and inside skins are brickwork.

Cavity Closure

An applied section usually fitted to the inside of the jamb section that extends the frame depth so that the window section spans the cavity.

Chamfer Board
A term used in Queensland to describe their own type of weatherboard.

(See Glazing Channel)

Colonial Bars
Horizontal and vertical bars fitted across window panes to give ‘period’ style effect.

Colonial Window
A window that is configured with horizontal and vertical bars to recreate the early colonial style of windows. It can be achieved with applied bars adhered to the glass or individually glazed.

Coupling Mullion
A vertical coupling member used to join two windows together.

Cover Plates
Usually vertical cover plates used to join two windows together. Not a coupling mullion. Used with or without a pipe staunchion.

Curtain Wall
A non-load-bearing window wall that is not a panel wall.


Daylight Opening
The clear daylight size that is visible through a glazed window pane.

Dehydrating agent within hollow spacer frames to absorb moisture from air within IGUs.

Double-Glazed Unit
Two panes of glass separated by an air or gas space designed to improve insulation against heat transfer and/or sound transmission. The air between the glass sheets is dried and the space is sealed, eliminating possible condensation and providing superior insulating properties.

A small, round wood unit with shaped ends, provided with a glue groove for joining together stiles and rails.

Drainage Slots
(See Weep Holes)


Edge Clearance
Nominal spacing between edge of glass product and bottom of the glazing pocket (channel).

Edge Seal
Seal around the perimeter edge of an insulating glass unit and the panes of glass.

External Glaze
A design which permits the glass to be glazed from outside the building.

Aluminium profiles used in a window. An extrusion is produced by pushing material through a die with an aperture of the shape of the section.


Factory Glaze
Windows that are glazed in the factory before delivery to site.

Federation Windows
A window that is configured to a style that recreates the early federation style of windows. Can be federation style glazing or profiled wide appearance framing or both.

The arrangement of windows and other openings on the external walls of buildings, especially the facade.

A piece of glass positioned such as to provide lateral support.

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.

An impervious membrane installed to prevent ingress of water into the building.

Flashing Fin
A perimeter fin that is an integral part of the frame extrusions. It has been normal practice for brick veneer houses that no additional flashing is normally required. (See also Reveal Fin)

Float Glass
Glass formed on a bath of molten tin. The two surfaces are flat, parallel and polished, giving clear, undistorted vision and reflection.

A support structure consisting of head, jambs and sill to form an opening into which glazing or door panels fit.


Gas Fill
A process in which argon or krypton is filled into the cavity of insulating glass to improve thermal performance.

Pre-formed shapes (e.g. strips) of rubber or rubber-like composition used to Fill and seal a joint or opening alone or in conjunction with a supplemental application of a sealant.

Glazing Bar
A member that is added to a standard window construction to change the appearance of the window. It can be in the form in which the glass is glazed, clipped, or stuck onto either or both faces of the glass.

Glazing Bead
Strip or trim surrounding the edge of the glass in a window or door that holds the glass in place.

Glazing Channel
Three-sided, U-shaped detail into which a glass product is Installed and retained.

Glazing Leg
The portion of the window section which is used to retain the glass in conjunction with the bead.


Equipment used in the opening, operating, closing, locking and stopping of sashes.

Head Flashing
Flashing installed in a wall over a window.

All horizontal members at the top of the window frame.

Head Rail
The top horizontal bar of a double hung sash or a door.

Heat Gain
Solar radiant heat, transmitted or emitted by glazing into a building, contributing to the building up of heat.

Heat Loss
The transfer of heat from inside to outside by means of conduction, convection and radiation through all surfaces of a house.

High Rise
A multi-storey building.


The movement of outdoor air into the interior of a building through cracks around windows and doors or in walls, roofs and floors.

Erection and fixing of window frame on site.

Insulating Glass Unit (IGU)
A hermetically sealed, multiple-pane glazing system consisting of two or more glazing layers held and bonded at their perimeter by a spacer bar. It is termed ‘insulating’ because thermal heat transfer is reduced compared with single glass.

Construction materials used for protection from noise, heat, cold or fire.

Any material used to bond two panes of glass and/or plastic together to form laminated glass.

Inter locking Stile
An upright frame member of a panel in a sliding glass door which engages with a corresponding member in an adjacent panel when the door is closed.

Internal Glaze
A design which permits the glass to be glazed from inside the building.


Sides of a window frame.

Space or opening between two or more adjoining surfaces.


An inert, non-toxic gas used in insulating windows to reduce heat transfer.


Laminated Glass
Two or more layers of glass permanently bonded with one or more polymer interlayer to form a single, unified glazing with improved safety and/or ultra violet protection properties.

Left Hand
To describe a component or design. It is always taken viewing the window from the outside.

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.

Alternative term for a pane of glass.

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

Low-e Glass
Low-emission glass (Low-e) is a clear glass; it has a microscopically- thin coating of metal oxide. This allows the sun’s heat and light to pass through the glass into the building. At the same time it blocks heat from leaving the room, reducing the loss considerably.

Low Lite
The portion of the window that is below the transom.


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

Meeting Rails
Horizontal Intermediate sash members that meet when the window is closed such that they combine to act in unison.

Meeting Stiles
Vertical intermediate sash members that meet when the window is closed such that they combine to act in unison.

Vertical framing member between window units.


Nailing Fin
An integral extension of a window or patio door frame which generally laps over the conventional stud construction and through which nails are driven to secure the frame in place.

National Fenestration Rating Council.


Obscure glass
Any textured glass (frosted, etched, fluted, ground, etc.) used for privacy, light diffusion or decorative effects.

Operable Window
A window that can be opened for ventilation.


Framed sheet of glass.

Panel Wall
A non-load-bearing window wall that is wholly supported at each storey.

Pascal (Pa)
The pressure or stress that arises when a force of one newton is applied uniformly over an area of one square metre.

Permanent Vent
A part of the window that provides ventilation even when the sash is in the closed position.

Picture Window
A large, fixed window framed so that it is usually, but not always, longer horizontally than vertically to provide a panoramic view.

Pivot Sash
Window units in which the sash hardware is located near the midpoint of the stile or rail to permit sash rotation.

Plastic Film
A thin plastic substrate, sometimes used as the inner layers in a triple or quadruple glazed window.

Prepared Opening
An opening in a building made prior to the installation of the window.

The plastic interlayer incorporated into laminated glass in order to ensure good adhesion and the mechanical and safety breakage characteristic of the glass.

‘Poly Vinyl Chloride’ is a material used for flexible (or rigid) glazing gaskets and weather seals.


Horizontal sash member.

The serviceability wind pressure in Pascals that when applied to the window will give the deflection and water penetration requirements of AS2047.

(See Glazing Rebate)

Adding or replacing items on existing buildings. Typical retrofit products are replacement doors and windows, insulation, storm windows, caulking, weather stripping, vents, landscaping.

The visible part of each side of a window opening not covered by the frame, or the recess between the frame and the face of the wall.

Right Hand
Describing a component or design. It is always taken viewing the window from the outside.

Rough Opening
The opening in a wall into which a door or window is to be installed.


Safety Glass
Glass constructed, treated or combined with other materials in order to reduce the likelihood of injuries If broken by human impact, etc. and meets relevant safety standards. Safety glass comprises toughened, laminated and wired glass.

Inner frame which holds glass in operable and fixed window units.

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.

Accomplishment of weather-tight protection between glazing or framing materials, usually by combinations of gaskets and sealant.

Elastomeric material with adhesive qualities applied between components of a similar or dissimilar nature to provide an effective barrier against the passage of the elements.

Sealed Unit
(See Insulating Glass Unit)

Side Rail
The vertical bar in a sash.

Sight Size
The actual size of the opening that admits day light.

Silicone Sealant
Sealant having a backbone of alternating silicon-oxygen atoms as its chemical composition.

Horizontal member at the bottom of a window frame or door.

Sill Flap
A vinyl seal fitted to the underside of the window to take up variations due to building settlement.

Single Glazing
Single thickness of glass in a window or door.

Site Glaze
Window glazed after installation of window into building.

Solar Heat Gain Coefficient (SHGC)
The total solar heat gain divided by exterior solar irradiance. It is composed of the solar direct transmittance plus the inward-flowing fraction of absorbed solar energy that is re-radiated, conducted or convected into the space.

Spacer Frame
Component of an Insulating Glass Unit (IGU) which maintains the width of space between the panes of the unit (See also Air Gap).

Small blocks of neoprene, EPDM, silicone or other suitable material, placed on each side of the glass product to provide glass centring, maintain uniform width of sealant bead and prevent excessive sealant distortion.

Standard Window
A window which is manufactured to a standard design and sizes.

Any bar which is added to stiffen the framework.

Stile (Sash)
A vertical side member of a sash.

The moulding on the inside of a window frame against which the window sash closes; in the case of a double-hung window, the sash slides against the stop. Also called bead, side stop, window stop and parting stop.

Storm Mould
A section which is added externally to seal the frame against the building. Usually has an integral flashing fin.

Structural Members
The elements, including mullions, transoms, meeting rails, and meeting stiles, that perform the function of transferring loads to the perimeter frame.

Structural Silicone Glazing
Use of a silicone sealant for the structural transfer of loads from the glass to its perimeter support system and retention of the glass in the opening.

Stud Opening
Opening size between timber studs in a building. It applies to vertical and horizontal openings.

Sub Sill
An under sill section that is used to raise the height of the sill to suit a specific building-in requirement. This is not necessarily a sump drainage sill.

Sump Sill
An under sill section applied to a window allowing it to gain sill depth for improve water performance. Standard sill drains out through this sump sill.


Tempered Glass
(See Toughened Glass)

Test Report
A report issued by a test laboratory detailing the tests that a window has undergone.

Thermal Break
An element of low conductance placed between elements of higher conductance to reduce the flow of heat. Often used in aluminium windows.

The member that lies at the bottom of a sliding glass door or swinging door.

Timber Reveal
The timber surround that is factory fitted to aluminium windows.

Tinted Glass
Glass with colorants (pigments) added to the basic glass batch that gives the glass colour, as well as light and heat-absorbing capabilities. The colour extends throughout the thickness of the glass.

Toned Glass
Alternative name for Tinted Glass.

Toughened Glass
Flat or bent glass that has been heat treated and quickly air- quenched to create compression in the outer surface and tension in the interior. If broken, it fractures into many small pieces. Toughened glass is approximately four to five times stronger than annealed glass of the same thickness when exposed to uniform static pressure loads and is classified as a safety glass.

A horizontal intermediate framing member of a window assembly.


Window supplied ex-factory without glass.

Term normally used to refer to one single assembly of an Insulating Glass Unit (IGU).

Unplasticised polyvinyl chloride, a rigid structural plastic which resists degradation under ultraviolet radiation; used for window frames and other building components. Same as PVC-u (European usage) and vinyl (North American usage).


Visible Face
Applies to extrusions and describes the visible area remaining on the section when the section is assembled into a window.

Visual Comfort
Refers to a set of qualities associated with the amenity of a window, such as freedom from glare and excessive contrast.

Polyvinyl chloride material which can be either rigid or flexible, used for window frames.


Water Penetration
A term used to describe the water performance of a window. Part of the standard testing procedure on a window calls for a water test.

A window shall not have water penetrate beyond the inner face after a 15 minute water test at a specified wind pressure. Minimum pressure is 150 Pa up to a maximum of 450 Pa.

Weather Flange
The portion of a section which acts as a weather barrier between opening sash and frame.

Weather Flap
A flap system within the sill of the window designed to allow water to escape and to prevent wind blowing directly back through the drain slots. Not to be confused with an under sill flap which fits under the window sill to allow for building settlement.

Weather Seal
A material included in a window assembly to reduce the air infiltration or improve resistance to water penetration.

Weather Strip
Thin sections of compressible material used to prevent air leakage around operable windows and doors.

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.

Weep Holes
(See also Drainage Slots) Drain holes or slots in sash or framing member to prevent accumulation of condensation and water.

Wind Load
The wind pressure in Pascals that the window has to meet. Wind load varies according to location and exposure.

Window Assembly
A complete unit comprising frame, couplings, sashes, glazing infill panels and hardware.

Window Dimension
The window frame size as shown on a brochure. Size is to overall frame size, not to overall reveal fin size. (H) refers  to window height (W) refers  to window width

Window Hardware
Various devices and mechanisms for the window including catches, fasteners and locks, hinges, pivots, lifts and pulls, pulleys and sash weights, sash balances and stays.

Window Labelling
Concept of implementation of standards and ratings for energy performance, weather-tightness, structural, acoustic and safety issues for window products.

Window Mould
Another way of saying Storm Mould.

Window Rating
(See also Rating)

Window Wall
A series of multi-light windows, generally from floor to ceiling and often continuous horizontally.