What does that mean?

Window & Door Terms

Argon Gas

Argon gas is a colourless and odourless gas that fills the airspace between double- or triple- paned windows. Because its very dense, it dramatically increases the thermal performance of windows.


Astragal is a moulding attached to the secondary side of double doors. It helps seal the space between the two doors and locks the secondary door from opening when you use the primary door.

Bay Window

A bay window is a set of three windows that project out from the house.

Bow Window

A bow window is a set of five or more windows that curve gradually outside the house.


A brickmould is an exterior trim for your windows and doors. It’s often used as a final design element or to retrofit a window/door without disrupting your home’s siding.

Casement Window

A casement window is attached by hinges on the side of the frame. It opens to the side with a crank handle.

Cam Handle

A cam handle is an L-shaped handle that’s primarily used on windows that push outwards.


Cladding is a coating of one material on another. It’s used to help with thermal insultation and weather resistance. 

Direct Glaze

Direct glaze refers to glass that’s been placed directly into a door frame. 


A doorlite is the glass that’s added into an exterior door.

Egress Window

An egress window is an emergency exit. It must be large enough for someone to fit through and is required in all bedrooms.

Flush Bolts

Flush bolts are located on the astragal of a door and lock/unlock the secondary door.

Garden Windows

A garden window protrudes slightly from the wall and lets in more light. It’s similar to a bay window, but smaller. 

Heel Dimension

The heel dimension is the actual size of a window.

Laminated Glasss

Laminated glass is a safety glass and stays together even when it breaks.


Mullion is a piece of vinyl that separates glass in a window.

Multipoint Lock

A multipoint lock enhances security by locking in multiple areas.

Rough Opening

A rough opening is a framed opening in your home/building where the window or door is going to be installed. They’re larger than the actual product to ensure there’s enough room for insulating and a proper fit.


The sash is the part of your window that slides.


A sidelite is a narrow window that’s located beside an exterior door. It’s usually built into the same frame as the door.

SDL (Simulated Divided Light)

SDL is a mixture of interior and exterior bars that mimic the look of individual glass panes. Because it’s made of one pane of insultating glass, it significantly decreases potential energy loss.


A spacer is a bar that’s placed between glass panes and creates an airtight space that’s filled with air or gas.


A snubber is a locking mechanism on casement windows.

Tempered Glass

Tempered glass is about four times stronger than normal glass and, when broken, breaks into pebble-like fragments that are relatively harmless (unlike normal glass which breaks into jagged pieces). 


T-bar separates doors and sidelights.