The following Glossary of Locksmith Terminology is provided courtesy of the Master Locksmith Association (MLA). Click on a letter below to be taken to its corresponding terms.

Cabinet lock - A generic term to include all locks of any type for use on pieces of furniture, such as cupboards, drawers, chests, boxes and the like.

Cam - Usually a tongue fixed to the end of the plug of a cylinder lock or latch.

Cam lock - A complete locking assembly in the form of a cylinder whose cam is the actual locking bolt.

Cap (of the lock) - The removable cover to a lock mechanism.

Case - That part of a lock or latch containing the mechanism.

Casement Door - A hinged door or pair of doors almost wholly glazed; often called a French Window.

Casement Window - A window in which one or’rhore lights are hinged to open.

Centres - The vertical measurement in an upright or sash lock between the centre of the keyhole and the centre of the follower hole.

Chamber - The holes in cylinder housings that house top pins (drivers) and springs.

Change Key - The key which opens one particular lock, the term is usually used with Master-Keyed Suites. (Servant key).

Change (of key) - See “Differ”.

Change Key Locks - These are locks which can be operated by any key chosen from a large number of different keys that have been made for the purpose. The selected key is the only one which will open the lock until a change is deliberately made.

Changing Key - One used in some keyless combination and change key locks to enable the combination to be altered.

Circlip - A ring with open ends which can be sprung into place on a plug or other part to permit rotation but to prevent endways movement.

Claw bolt - A type of deadbolt having pivoted claws which swing out sideways when the bolt is shot. Such locks are usually fixed to sliding doors.

Clutch headed screw - Threaded screws suitable for wood or metal with a shaped head allowing clockwise action to fix but no anticlockwise action to remove.

Close shackle padlock - A padlock, the body of which is built up so that the minimum amount of shackle is visible when locked. It offers improved security against forcing or use of bolt-croppers.

Coined - A term which signifies embossing, that is, the forcing of cold metal between dies to give it form without cutting the metal. The impressions on coins at the Royal Mint are made in this way - hence the name - and so are those on the bows of cylinder keys.

Collar - The shoulder on the shank of a rim, mortice or bitted key, controlling the point at which the key comes to rest after being fully inserted into the lock. The collar is the datum point from which the key is measured.

Collar - Ward A side ward cut closest to the pin adjacent to the collar.

Combination Lock - An abbreviation of name for a keyless combination lock.

Concealed fixing (of locks or latches) - A strong backplate is screwed to the door, the lock case slides over it and is secured in position by two or more grub screws which are concealed whenever the door is closed. This is usually associated with security nightlatches.

Connecting bar - The thin metal strip fitted to the rear of the plug which transmits the motion from the tumbler mechanism of the cylinder to the springbolt in the case of a cylinder rim latch or lock. It passes through the thickness of the door, and is usually indented at intervals to facilitate shortening to the correct length.

Connecting screws - The two screws which fix the cylinder body to the backplate.

Cover - The part of a lock or latch which covers the mechanism and is fixed, usually by screwing, to the case.

Cross differ - An error situation whereby change keys (servant keys) operate more than one lock when this was not intended.

Cross rail - The horizontal member of a door.

Cross suiting - This is a departure from straightforward master keying and is best explained by examples of cases which often occur:
1. Two or more different servant keys are required to pass one lock, all being in the same suite or subsuite.
2. One servant key is required to pass two or more different locks, all being in the same suite or subsuite.
3. A servant or submaster key of one subsuite is required to pass one or more locks in another subsuite.

Cut cabinet lock - A cupboard or drawer lock, the flange of which is recessed into the edge of the drawer or door.

Curtain - An abbreviation for barrel and curtain.

Cylinder - Usually the cylinder with inner co-axial plug which houses the pins, top pins (drivers), or disc tumblers and springs in the cylinder body.

Cylinder housing - With all component parts removed, this forms the main body or housing of a cylinder.

Cylinder key - A key, having a bow and long blade in which Vee cuts are made along the upper edge to operate the pins and drivers in a pin tumbler mechanism.

Cylinder lock or latch - Any lock or latch, the mechanism of which is contained in a cylinder.

Cylinder rose - (or ring) A shaped metal disc which surrounds the outer face of the cylinder of a cylinder mechanism assembly. ft usually stands slightly proud of the outside face of door.

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