Lever Lock Glossary

This is intended to be a limited glossary for those beginners and intermediates in locksport who may be encountering lever locks for the first time.



Backplate - The part of the lock - the plate - that is fixed onto or into a door, to which the moving parts of a lock or latch are attached.

Backset - The horizontal distance from the outside face of the outer forend to the centre of the keyhole or follower hole (or both). Designated as the keyhole backset” or follower backset”.

Barrel - see curtain

Beard - The parts of the flag that remain uncut after it is bitted

Belly (of lever) - The part of the lever (usually curved) that interacts with the key

Bit/Bitting - The parts of the flag of the key that is cut to different heights to operate the levers

Bolt - The part of a lock or latch which provides the fastening or engagement by protruding from the case or forend to engage in the staple, striking plate, link, shackle or other members.

BS3621 The British Standard specification for Thief Resistant Locks

Box lock - This is a variation on the cabinet lock in which the striker plate protrudes into the lock body


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.

Curtain - A part of some lever locks that rotates with the key, controlling and limiting access to the interior of the lock

Cheek-plate - The (often removeable) metal faces of the lock casing through which the key passes


Detainer - A generic term, particularly used to describe Chubb-type levers with an open lever

Differs  - An abbreviation of different combinations” or changes.

Double Bitted Key - One with a bit on each side of the shank.

Double-handed lock - This has two uses - A lock designed for use either as a right or left-hand installation without alteration, generally by turning upside down. The keyhole has a circular formation at each end of the slot to accept the shank of the key. Common with 2 and 3 lever locks

Drillpin/Pin/Post - The metal pin in a lock over which the hollow shank of a key slides - this locates the key and offers resistance to the torque action of the levers. Alternatively the cheek-plate of the lock performs this function


Escutcheon — The cover for the keyhole of a lock


Forend/faceplate - That part of the lock or latch through which the bolt(s) protrude, and by which the lock or latch is fixed to the door.

False Gates - The extra gaps in lock levers and/or bolt stump of some locks to improve pick resistance.

Flag - The section of the key, that is bitted, and interacts with the levers

Flat/plate key — A key made from steel sheet or strip.


Gate — The gap in a lever or detainer that allows the stump of the bolt to pass in the action of moving the bolt.

Guard — A guard is a contrivance to prevent false keys from turning, or to prevent a pick from interacting with the bolt or levers. See also Ward”

Gauge – Most keys have a 7g or 5g shaft. This is a measure of the diameter of the key shaft and therefore the hole in the lock


Handing - Handing is the term used to describe the indication of which side of a door the hinges are placed and whether the door opens inwards or towards you. With reference to picking locks this affects which side of the lock you may be approaching and hence where the bolt is in relation to the levers.





Lever - A flat shaped movable detainer in a lock. The lever(s) in a lock have to be actually moved by the key to operate the lock. The belly of the lever is cut away to various depths to provide different combinations. The lever interacts with the stump to control motion of the bolt

Lever Pivot/stump — The pin in a lock on which the levers swing


Mortice lock - A lock or latch which is morticed or let into the thickness of the door from the meeting edge and held in position by screws through the forend.



One-sided lock - A lock which has a keyhole on one side only.


Pin key — A key with solid shank

Pipe key — A key with a hollow circular shank to locate on the drillpin


Relocker - A locking mechanism that is independent of any key operations, and acts so as to relock the boltwork under certain forced attacks.

Rim lock or latch — A lock or latch that is fitted by screwing on to the inside face of the door - as opposed to the mortice which is recessed into the door structure. These tend to be 2 or 3 levers and used for internal doors and light security. Old church locks are often in this category.


Safe Lock - A general term for the many varieties of key operated and other locks for safes.

Sash lock - An upright mortice lock, consisting of a latch bolt and a key operated bolt.

Shank (of key) — The part of a pin or pipe key between the bow and the end, excluding the flag.

Shoot - The outward movement of a lock bolt and the distance which it travels under the action of a spring or key. Also used to refer to the distance a springbolt moves under the action of its spring.

Side Wards - Notches cut into the sides of bitted keys so fashioned to enable the key to turn.

Springbolt/latchbolt. - A bolt constructed such that it can be pushed back into the case and return to the extended position. This allows the lock to act as a latch

Stump - a section of the lock attached to the bolt that interacts with the Levers to control access


Talon - The gap in a bolt or runner of a lever lock in which the key sits to engage the bolt.

Throw — The distance a bolt moves under the action of its key. A double throw bolt is one where two turns of the key advance the bolt by one throw each.


Wards - Fixed obstructions inside a lock, sometimes used in lever locks to give increased differs.

Warded lock - Some locks or padlocks, make use of wards only for security.