Glossary of Terms for Doors, Windows and Hardware

Access Control

Any barrier or device that prohibits or restricts, free or unlimited access.

Access Control Cylinder

Cylinder, which features electronic access control. It allows the main lock to operate without additional wiring and no hardware changes and modifications.

Access Control Key Fob

Any device other than a key operating access control systems.

Active Leaf

Also referred to as a Master Leaf, Lead Leaf or Main Leaf. It is the single door of a pair normally having the main hardware fitted on it and controlling how the locking system operates.


Usually connected to the cylinder, which enables the lock system to operate.

Architectural Hardware

Also referred to as Architectural Ironmongery. These are handles or other fittings that are fixed to doors and windows.

Automatic Closing

A door fitted with a closer or other devices which removes the need for manual closing.

Automatic Deadbolt

A deadbolt designed to operate when the door is closed.

Automatic Flush Bolt

A flush bolt designed to operate when the leaf upon which they are fitted is in the closed position.

Auxiliary Lock

Any lock installed in addition to the primary lockset.

Back Plate

A thin piece of metal, usually with a concave portion, used with machine screws to fasten certain types of cylinders to a door.


The resistance provided by a door closer as a door is opened


The distance from the centre of the Cam (or spindle) to the front of the lock.

Bi-Fold Door

A door with two or more sets of hinges, the additional set(s) allows the door to have an accordion action when opened.

Bottom Pin

Usually a cylindrical shaped tumbler which may be conical, ball shaped or chisel pointed on the end which makes contact with the key

Cam Lock

A complete locking assembly in the form of a cylinder whose cam is the actual locking bolt

Card Access System

An access control system that utilizes a controlled security card as the credential.

Card Reader

A device which interprets coding resident on or in cards.

Lock Case

The housing or body of a lock.


Any device that holds a door closed and may be released by simply pushing or pulling on the doo

Clear Opening

A portal providing clearance through which passage is unhampered.

Closer Size

A numerical value related to the applied force of a door closer, with a larger number being a stronger force. Older closers were assigned alphabetic size designations, where A was the smallest.

Combination Lock

A lock which is operated by local input of a specific series or sequence of numbers or letters.

Continuous Duty

Designed to sustain application of power for extended periods.


In conjunction with a pair of doors, a device designed to cause the inactive leaf to close first.

Deadbolt or Dead Bolt

1. A bolt on a lock that is moved by turning the key or knob without activation of a spring. 2. The part of a lock that is engaged or withdrawn with a key.


A kind of latch whose bolt may be so locked by a detent that it can not be opened from the inside by the handle, or from the outside by the latch key.


A single point lock normally in the form of a bar or bolt or a lock which operates a deadbolt


A feature which, when fully engaged, resists attempts to move the latch or bolt in the unlocking direction through direct pressure.

Deadlocking Latch

A latchbolt with a deadlocking mechanism.


To place an exit device in the holdback mode. In marine applications this can also be termed as the latch for a hatch.

Dogging Cylinder

A key operated cylinder used to dog an exit device.

Dogging Device

In an exit device, a mechanism used to temporarily disable the latch from locking.

Dogging Key

A key or tool used to dog an exit device.

Dogging Screw

A screw used to dog an exit device.

Door Bumper

An obstacle fitted to prevent a door or lock from contacting another object such as an opening door causing damage to a wall.

Door Closer

A device designed to control the closing of a door automatically by various means.

Door Control

Any device which controls the opening, closing or position of a door.

Door Swing

The direction and degree to which a door opens

Door Holder

Any device designed to maintain a door in the open position.

Door Viewer

A device with one or more lenses, mounted in a door at eye level, which allows a limited view through a door.

Double Cylinder

A cylinder which accepts a key on both sides or also a lock with two keyed cylinders.

Double-Acting Closer

A door closer designed to enable a door to swing both ways, in and out.

Double-Acting Door

A door with the ability to swing both ways, open in and out.

Dummy Cylinder

A cylinder which has no function, used for cosmetic appearance only.

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Electric Strike

An electro-mechanical strike, which secures or releases the latch via applied current.

Electrified Lockset

A lock which is controlled electrically.

Electronic Access Control

Access control that uses electricity.

End Cap

The cover typically used on the hinge side edge of many touch bar exit devices.


A surface mounted trim which enhances the appearance and/or security of a lock installation.


A top and bottom locking system with hooks at either end which rotate to draw a door or window fully closed.

Exit Alarm

An annunciator that signals the opening of an exit door.

Exit Device

A door lock/latch mechanism which releases in the direction of exit travel via a bar or panel extending across the major width of the door.

Exit Door

A door which has no provision for enbtry into a building or a door which fills some or all the code requirement for safe egress of the occupant load from a building or portion of a building.

Exit Only

Refers to hardware designed to secure an opening in such a way as to permit exit at all times but prevent entry at all times.

Exit, Direction Of

The way occupants are expected to move to get out of a building .

Face Plate

The finished, removable plate which covers the front of some locks.

Factory Original Key

The out key furnished by the lock manufacturer for a lock or cylinder.


A feature of a security device designed to release, for safety purposes, during a power loss.


A material, coloring and/or texturing specification.

Fire Exit Hardware

Exit devices, which may legally be installed, on fire doors. These are identified separately from other exit devices due to them being suitably labeled for both fire or panic exit and there is no means of dogging the device.

Flush Bolt

A non-keyed deadbolt, with a one piece escutcheon/faceplate, typically mounted flush to door surfaces.

Flush Pull

A recess in a door or drawer that serves as a handle or grip.

Grand Master Key

The key which operates two or more separate groups of locks, which are each operated by a different master key.

Grand Master Key System

A master key system which has exactly three levels of keying


Hardware that is manufactured only for application on doors with a specific direction or orientation.

Hardware Schedule

A listing of the door hardware used on a particular job it includes the types of hardware, manufacturers, locations, finishes, and sizes. It should include a keying schedule specifying how each locking device is to be keyed.

High Security Cylinde

Cylinder which offers a greater degree of resistance to any two or more of the following: picking, impressioning, key duplication, drilling or other forms of forcible entry.

Hinge Stile

The vertical edge of a door where hinges are installed or a concealed closer and threshold pivot positioned.

Hold Open

A door closer, or separate hardware device, which allows the door to be retained in an open position.

Hold Open Arm

A door closer arm with the capability of maintaining the door in the open position.

Hold Open Cylinder

A cylinder provided with a special cam which will hold a latch bolt in the retracted position when so set by the key.


A function of some self latching locks which allows selective retention of the bolt to prevent latching when the door is closed.

Hook Bolt

A lock bolt shaped in the general outline of a hook. Normally used on sliding doors or where spreading of the frame and door is a possible attack.

Inactive Door

Also referred to as a slave leaf, the door of a pair, which is secondary in usage and is normally locked by surface or flush bolts.

Intermittent Duty

An electric strike or lock not designed to be energized for extended periods of time.


One of a pair of vertical posts or pieces that together form the sides of a door, window frame, or fireplace, for example.

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Keyed Alike

Two or more looks or cylinders which have or are to have the same combination. They may or may not be part of a keying system. KA is often used as an abbreviation.

Keyed Different

A group of locks or cylinders, each of which is or is to be keyed differently from the others.

Key Blank

A key which has not yet been cut to work with a cylinder.

Key Override

The ability to override the normal function of a lock by means ofa key.

Keying Schedule

A detailed specification of the keying system listing how all cylinders are to be keyed and the quantities, markings, and shipping instructions of all keys and/or cylinders to be provided.

Kick Plate

A protective plate mounted on the bottom of a door to prevent damage to minimize damage to the door.

Latch Bolt

A spring actuated bolt, normally with one or more beveled surfaces, which, when aligned with the strike, engages it automatically.

Latch Guard

A plate or combination of interlocking pieces designed to block access to the edge of a latch when the door is shut.

Master Key System

A keying arrangement which has two or more levels of keying.

Master Key

A key that opens every one of a given set of locks.

Multi-Point Lock

A lock which has more than one bolt which are thrown and withdrawn simultaneously, often in more than one direction or a key which operates all the master keyed locks or cylinders in a group, each lock or cylinder usually operated by its own change key.

Night Latch

A rim mounted auxiliary latch bolt.


Hardware that is manufactured in a way, which allows installation on doors of any orientation without requiring modification or adjustment to accommodate the door orientation.


Door hardware whose hand cannot be changed in the field.

Override Code

An an electronic lock, a factory-set or user-set combination that will always open the lock.

Override Combination

In certain locks with a user changeable combination, a second combination which allows access at all times. It is usually factory set and may not be field changeable.

Positive Latching

The condition of a door being secured such that manual operation of the latch or bolt mechanism must occur before it may be opened.

Positive Locking

When a key cut which is too high forces its tumbler into the locking position.

Push/Pull Plate

A flat trim mounted for hand contact to push open a door.

Remote Release

A mechanism for permitting the unlocking of any lock device at a distance from the device.


Hardware that is manufactured in a way, which allows field assembly or adjustment to accommodate installation on doors with different orientations.

Self Closing

Doors or covers which have a continuous force applied in the closing direction


A component which transfers rotary motion from outside a lock or latch case to an inner mechanism.

Split Spindle

A multi piece spindle which allows a knob or lever to be installed on only one side of a door.


A bolt receptacle typically mounted in the door jamb or the floor.


The distance a bolt or latch projects from the faceplate or case of a lock in the extended position.

Thumb Turn

An actuator which can be turned by thumb and forefinger.

Thumb Turn Cylinder

A cylinder with a turn knob rather than a keyway and tumbler mechanism.

Time Delay

A feature which prevents operation until a set amount of time has elapsed. Activation normally begins when access, egress or other unlocking is desired.

Time Delay Lock

A lock that has a mechanism for preventing unlocking until a specific amount of time has passed.

Touch Bar

A type of exit device actuator which typically does not pivot and retracts the bolt with a minimum of pressure.

Vertical Rod Exit Device

An exit device with bolts typically at the top and bottom of a door connected to a central mechanism by rods.