A Complete Vocabulary of Door Components

Here is our ever-growing glossary of door components and terms you may encounter when researching the right doors for your project, home or business.

FSE Special Purpose Doors are experts in all aspects of door manufacture and installation. We have expertise in fire doors, solid core doors, heritage door upgrades, acoustic doors, and radiation-shielded doors.

Our customers benefit from many years of experience in product development, manufacture, design and installation. We can provide consultation expertise for building designers, architects, specifiers and engineers ensuring our customers receive a truly “fit for purpose” solution.

Here is a comprehensive glossary of door components and terms that you may come across when researching the right doors for your project, home or business. Of course, if you have any questions about anything to do with doors, contact the experts here at FSE.

Vocabulary of door components


Acoustic DoorAcoustic doors are soundproof doors that provide sound insulation to protect your employees, visitors and other general public members from potential noise pollution.

Active Door – The leaf of a pair of doors – also known as double doors  – that opens first and contains the locking or device.

Adhesive – A sticky substance that holds materials together.

Architectural Door – A door built to a higher standard than traditional doors that you would find in a home or your average commercial building.

Astragal – Moulding or a wooden strip that is attached to a door to stop it from swinging past its axis.


Backset – A measurement from the edge of a door to the centre of the hole drilled for a lockset or deadbolt.

Bevel – The edge of a door that is not cut at a right angle.

Bifold – A door that can be folded in the middle. They are attached by hinges to allow movement.

Butt – A door hinge designed for mortising into the edge of a door and into the rabbet of a door frame.


Doorset – A complete door assembly that includes door leaf, glazing, panelling and any other features, all door hardware, the door frame, and fixed panels.

Door Height – The vertical height of a door.

Door Size – The combined dimensions of a door, ordered like this: height (mm) x width (mm) x thickness (mm)

Door Thickness – The cross-sectional thickness of a door panel.

Door Width – The horizontal width of a door.

Double Rebate – A frame with rebate provisions on both sides of the frame.


E-core – E-Core is a versatile vermiculite based homogenous core for fire doors.


Fire Rated Doors – A door that has been tested following the relevant standards and has been given a fire resistance rating.

Fire Resistance Level  – The graded level (time) of a door’s fire resistance that is determined by testing a door against the standard time-temperature curve regime as set out in AS 1530.4.

Frame Profile – The cross-section of a door frame.


Leaf – The single moving part of a door.


Mullion – The vertical section of a frame that separates a frame opening into two different sections.


Opening Height – The vertical height of a door opening.

Opening Size – The combined dimensions of a door opening, ordered like this: height (mm) x width (mm) x thickness (mm)

Opening Width – The horizontal width of a door opening.


Rebate – The section of the door frame that accommodates the door leaf.

Return – The section of the frame that backs onto the wall.


Stop Height – The part of a door frame that protrudes into the opening, adjacent to the rebate.

Stop Section – The section of a door frame between the rebates.


Throat – The distance between the returns of a door frame, measured in millimetres.

For enquiries or assistance about doors for your building, please contact FSE Special Purpose Doors at [email protected] or call +61 2 9905 8222. We supply and deliver fire doors to Sydney and throughout Australia.

Learn some more about the world of fire doors below:

How To Spot A Fire Door Quickly

15 Facts About Fire Doors You Didn’t Know

All Your Fire Door Questions Answered