abb. bow-to-tip
B label
n. a classification by Underwriters Laboratories for doors with 1 1/2 hour rated fire protection
back plate
n. a thin piece of metal, usually with a concave portion, used with machine screws to fasten certain types of cylinders to a door
n. the resistance provided by a door closer as a door is opened
n. the distance between the center of a cross-bore and the bolt edge of a door or drawer
n. a device or devices designed to deter the retrieval of items through a depository opening
balance (a combination)
v. to dial a combination 1 number high and 1 number low to verify a correct combination setting
balance hole
n. the place in a combination wheel where material has been eliminated to provide an equal distribution of weight over the entire wheel relative to the axis
balanced pinning
n. a process used to ensure that all pin stacks are, or nearly are, equal
ball bearing
n. 1. a metal ball used in the pin stack to accomplish some types of hotel or construction keying, 2. a ball, usually made of steel, used by some lock manufacturers as the bottom element in the pin stack in one or more pin chambers, 3. any metal ball used as a tumbler's primary component, 4. used as a means of repairing a drilled hole in a safe when welded in place
ball bearing hardplate
n. a hardplate that contains metal balls, typically two types, imbedded in a honeycomb pattern, or free moving within a hardplate envelope
ball bearing hinge
n. a hinge which uses ball bearings between its knuckles to reduce friction
ball catch
n. a latch which uses spring pressure to force a ball bearing into a recess in its strike
ball check
n. a spring loaded ball bearing in a door closer arm assembly that acts to limit arm travel
ball locking
adj. a method of locking a padlock shackle into its case using ball bearing(s) as the bolt(s)
barium ferrite card
n. an access control system credential consisting of magnetized ferrite embedded in a plastic card with polarity and location being important features
barrel bolt
n. a surface mounted slide type which has a cylindrical shape
barrel key
n. a type of bit key with a hole drilled into the shank from the tip
barrier free
n. having to do with the absence of restrictions to access by the handicapped
Barron, Robert
the Englishman credited with the invention of the double-acting lever tumbler in 1778
Basic Building Code
n. former name for BOCA National Building Code
battery eliminator
n. an electric device designed to provide energy to equipment normally requiring electric power storage devices for operation
abb. Basic Building Code
abb. bolt control handle
bell box
n. the protective enclosure for a bell or other alarm sounding device
Bell type key
n. a key whose cuts are in the form of wavy grooves milled into the flat sides of the key blade. The grooves usually run the entire length of the blade.
bevel (of a door)
n. the pitch on the leading edge of a door which allows clearance for closing
bevel (of a lock)
n. the pitch of the face designed to match the pitch of a door edge. In some locks it is adjustable.
n. a threaded collar commonly used to secure certain cylinder or lock assemblies
abb. Builders Hardware Manufacturers Association
n. that portion of the cylinder shell which normally houses the pin chambers, especially those of a key-in-knob cylinder or certain rim cylinders
bicentric cylinder
n. one which has two independent plugs, usually with different keyways. Both plugs are operable from the same side/surface. It is designed for use in extensive master key systems.
bicycle padlock
n. one with sufficient shackle clearance to secure a bicycle
bi-directional cylinder
n. a cylinder which may be operated in a clockwise and counterclockwise direction by a single key
bi-fold door
n. a door with two or more sets of hinges, the additional set(s) allows the door to have an accordion action when opened
bilevel capable
n. typically a key that can operate two compatible mechanisms which have different security features
binary cut key
n. a key whose combination only allows for two possibilities in each bitting position: cut/no cut
binary type cylinder or lock
n. one whose combination only allows for two bitting possibilities in each bitting position
adj. of or pertaining to a lock with a hybrid mechanism, part of the mechanism identifies a physical attribute such as finger print, voice print, etc. while another part is a mechanical mechanism
n. 1. the part of the key which serves as the blade, usually for use in a warded or lever tumbler lock 2. v. to cut a key
bit height
n. a measurement from the post of a bit key outward to the end of the bit
bit key
n. a key with one or more projecting bits
bit thickness
n. a measurement of the bit from one side to the other side
bit width
n. as inserted into a lock, a measurement from the leading edge to the trailing edge of a bit
n. 1. the number(s) which represent(s) the dimensions of the key 2. the actual cut(s) or combination of a key
bitting depth
n. the depth of a cut which is made into the blade of a key
bitting list
n. a listing of all the key combinations used within a system. The combinations are usually arranged in order of the blind code, direct code, and/or key symbol.
bitting orientation
n. the specification of how a written combination is to be applied to a key (tip-to-bow, etc.)
bitting position
n. the location of a key cut as dimensioned from the stop of the key, and irrespective of cut depth
n. the portion of a key which may contain the cuts and/or millings
adj. uncut, see also "key blank"

blade height
n. 1. in a cylinder key, the distance from the bottom of the blade to the top of the uncut surface, 2. in a multiply bitted key, the distance from a registration point to the top of the uncut surface

blade length
n. in a cylinder key, the distance from the tip of the key to the bow stop or the bow

blade width
n. in a cylinder key, the distance from one non-bitted surface to the opposite non-bitted surface

lind code
n. a designation, unrelated to the bitting, assigned to a particular key combination for future reference when additional keys or cylinders may be needed
block master key
n. the one pin master key for all combinations listed as a block in the standard progression format
blocking lever
n. a lever in a safe deposit lock which blocks the renters key from completely entering the lock until the guard key has been inserted and turned
abb. block master key
abb. Building Officials and Code Administration International (formerly Basic Building Code)
BOCA National Building Code
n. the model building code developed and published by BOCA
n. any movable projection which blocks the movement of one object relative to another
bolt control handle
n. a lever or wheel shaped device on a safe or vault door that is used to extend or retract the boltworks
bolt cup
n. a thimble shaped device in a safe door frame that a locking bolt extends into when the door is closed and the bolt(s) are extended
bolt head
n. the part of a bolt that enters a strike 
bolt motor
n. 1. a mechanical device that extends and retracts the door bolt(s)of a safe, normally engaged by closing the door and disengaged by a time lock, 2. a mechanical device (usually electrically powered) that extends and retracts the bolt of a safe lock. It is commonly disengaged by an electronic input such as that from a keypad.
bolt sensor switch
n. a switch installed to detect when a lock bolt is extended or retracted
bolt shim
n. a plate or plates mounted to the frame of a vault to provide equal gapping for each locking bolt
bolt tail
n. the part of a bolt retained in the lock case that contains the bolt slot and maintains bolt alignment
boltwork button
n. the component which automatically triggers extension of the locking bolt(s) when the door is in the closed position
n. 1. the combination of bars, rods, plates and linkages in a safe door designed to hold the door in the locked or unlocked position depending on the status of the lock itself, 2. any part of a lock other than a cylinder, turnpiece, or operating handle that affects movement of, or the ability to move, the bolt
bond box
n. the removable container within a safe deposit box compartment
bored lock
n. a lock for a door prepared with one or more cross-bores and one or more edge-bores
n. an internally lighted optical instrument for viewing normally concealed or inaccessible components
boring jig
n. a tool, temporarily affixed to a door, which provides a template structure to guide drill bits properly when preparing for the installation of specific hardware
bottom of blade
n. the portion of the blade opposite the cut edge of a single bitted key
bottom pin
n. usually a cylindrical shaped tumbler which may be conical, ball shaped or chisel pointed on the end which makes contact with the key
v. a method used to open certain safes involving dropping the safe and relying on gravity and inertia to move the bolt and open the safe
n. the portion of the key which serves as a grip or handle
bow stop
n. a type of stop located near the key bow
bow to tip
n. a specification that a bitting combination is recorded starting at the bow and proceeding to the tip
box of wards
n. a complete unit of intricate wards installed in or on a lock case
box strike
n. a strike equipped to line the bolt cavity for both aesthetic and protective purposes
brace Lock
n. a deadbolt lock that engages an independent bolt, one end of which is mounted in the floor away from the door
Bramah, Joseph
the Englishman who had the world's first patent of a locking mechanism in 1784. It was the first lock incorporating a cylinder whose key did not contact the lock bolt directly.
Bramah type lock
n. a lock or cylinder using a mechanism with sliders, normally arranged in a circle
bridge assembly
n. a removable frame that contains the wheel pack and wheel post that is often found in mechanical vault locks
bridge ward
n. a center ward attached to the interior of a lock by means of a bracket
Brink function
n. a handed cylinder design to allow a change key to turn in one direction only, while allowing the master key to turn in both directions
n. 1. a tool used to cut the keyway into the cylinder plug 2. v. to cut the keyway into a cylinder plug with a saw like tool
building master key
n. one which operates all or most master keyed locks in a given building
build-up dimension
n. 1. the distance between two different shear lines, as expressed in units of the manufacturer's increment or as an actual measurement, 2. the dimension of the pin required in a particular chamber, which will allow one key to operate at the plug shear line and a different key to operate at a different shear line
build-up pin
n. the additional element of a pin stack required to allow operation at different shear lines in a cylinder
bullet catch
n. a projecting friction latch which is spherical or dome shaped
bump key
n. a lock picking key with uniform steeples between cuts that is forced further into the lock via impact
burglar alarm
n. a system designed to detect and report conditions, which may indicate intrusion or attempted intrusion
burglar chest
n. a small safe, typically with a UL rating, designed to resist burglary attempts
burglar resistant
adj. of or pertaining to a security container designed to resist forcible entry for a specified period of time determined by the rating of the container
button knob
n. the knob in a key-in-knob lock that includes a push or turn button
buzzer plate
n. an automotive ignition component that triggers an alarm when the key is in the ignition and a door is open without the engine running
bypass key
n. the key which operates a key override cylinder
by-pass tool
n. a device that neutralizes the security of a locking device, or its application hardware, often taking advantage of a design weakness
by-passing door lock
n. a lock with a bolt that extends to block parallel movement of another door
by-passing sliding door
n. Two doors mounted on tracks parallel to each other that when one or both are slid to opposite extremes block the opening. Typically, one may be moved behind the other to allow access.


A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Appendix

This listing of the Locksmith Dictionary is courtesy of