Glossary of terms in alphabetical order


ANSI Standard

Approved American National Standard - American National Standards Institute "ANSI" for Mortise Locks and Latches Series 1000; ANSI implies a consensus of those substantially concerned with its scope and provisions.  It is intended as a guide to aid manufacturer, the consumer, the general public. Its scpoe includes operational & material tests, cycle & finish tests, dimensional criteria. 


The measurement used on nightlatches and mortise locks.

Bathroom Lock

A mortise lock can be used with thumbturn handles to allow the occupant of the bathroom to lock the door from the inside.

BS EN 1303

This standard classifies cylinders using a 7 digit coding system.  Each digit refers to a particular feature of the product measured against the standard's performance requirements.  The standard includes tests on durability, fire and corrosion resistance.

BS EN 1935

This standard provides details on product types, classification by use, test cycles, door mass, corrosion resistance, as well as definitions, product performance requirements, test apparatus, test methods and marking of products. In addition, the published standard includes annexes with details for special applications.

Butt Hinge (for doors)

Hinges are designed for timber doors, purchased pre assembled and fitted on site to enable doors to be hung

Carbon Steel

An alloy which is used in the manufacture of window hardware, usually being coated to increase its corrosion resistance.

CE Marking

CE Marking on a product is a manufacturer's declaration that the product complies with the essential requirements of the relevant health, safety and environmental protection legislations, in practice by many of the so-called Product Directives.



The deadbolt is located at the centre of the lock to add increased security. Normally of rectangular shape but can also be in the shape of a hook.


A mortise deadlock does not have a latch, but a bolt only which is operated by key.

Some nightlatches have a deadlocked function that adds extra security to the locking mechanism after the key has been rotated for a second time.

Door Chain

A fitment that restricts the door to being partially opened in order to identify callers prior to opening the door for access. Can be either an integral part of the lock mechanism or surface mounted on the inner face of the door.

Electric Strike

An electrical device that permits releasing of the lock in the door from a remote control.

EN Standard

European Standards as a guide to the manufacturers, consumers and retailers.  It includes operational, materials, cycle tests and dimensional criterion.

Euro Profile Cylinder

A cylinder barrel with a specific shape that can be fitted and used in many types of locks including mortise locks.


The exposed surface of a mortise lock which shows in the edge of a door after installation.

Flag Hinge (for doors)

Door Hinge system used on PVCu Doors which allows for easy installation and adjustment.



Hook shaped bolts used on a lock, designed to assist door compression and a high level of security against forced attack


Laminated Glass

A type of “safety glass” much stronger than float glass, made up of two layers of glass bonded together with a tough plastic film.


Most mortise locks have an easily reversible latchbolt for securing the door so that it can still be operated by handle from either side.


Levers are used in some mortise locks and padlocks.  The higher the number of levers a lock contains, the higher the level of security it offers.


Master Key

One key that operates a number of locks where the individual locks each have their own, different key.  For further information, contact your locksmith.

Mortise Lock

The lock fits into a mortise that has been ‘cut out’ of a timber door edge. The locking action is achieved by a bolt that shoots out of the lock into the striker plate when the key is turned.


Multi-Point Lock

Describes a type of lock mechanism that has more than one locking point.  It usually has a minimum of three locking points (plus latch) spread strategically over the length of the door.  Multi-point locks are typically used on PVCu or composite doors.


A lock which is mounted onto the surface of the door as opposed to being morticed into the edge of the door.  A nightlatch holds the door shut on a latch which can often be deadlocked into position.

Nightlatches are still sometimes referred to by their traditional name of 'rimlock' although a rimlock usually now refers to a basic security lock for use on internal doors, gates or outbuildings.


Rim Lock

Nightlatches are still sometimes referred to by their traditional name of 'rimlock' although a rimlock usually now refers to a basic security lock for use on internal doors, gates or outbuildings


Safety Glass

A glass that is designed to reduce the risk of injury when broken.

Secondary Glazing

An additional layer(s) of glazing fixed to an existing window to produce a thermal/acoustic break. This is not double glazing.


The spindle is a square metal bar which connects the door handles on either side of your door together through the follower.  When the levers of your door handles are pressed, the spindle rotates and operates the latch inside the door, allowing the door to open.

Tempered Glass

A type safety glass that has undergone a heat treatment process in order to increase its strength. Also known as toughened glass.

Thumbturn Cylinder

A knob fitted to one end of a cylinder which allows the door to be unlocked without a key from one side only