Glossary
Pin and Ward by Joshua Spahr is an educational encyclopedia of locks and security hardware. This A–Z glossary defines terms used across the articles. It is educational only — vocabulary and context, not how-to instructions for opening, bypassing, or defeating locks.
A
Abloy:
Brand/mechanism family strongly associated with disc-detainer cylinders.
See also: Disc Detainer
Access Control:
Systems and policies that decide who may enter which door at which times, typically combining credentials, controllers, and locking hardware.
See also: Access Control
Access Control Panel:
The controller that evaluates credentials and drives locks/readers according to schedules and permissions.
See also: Access Control
Active Leaf:
In a pair of doors, the door or doors in which the latching device is installed; also referred to as an Active Door.
ADA (Doors/Hardware):
Americans with Disabilities Act requirements affecting door hardware operability, clearances, and accessibility — already listed live as Americans with Disabilities Act; this tag clarifies hardware relevance.
See also: Latch
All-section Key Blank:
The key section that enters all the keyways of a multiplex key system.
ALOA:
Associated Locksmiths of America, Inc.
Alternating Parity:
Most often describes the type of mathematical progression employed to develop master key systems. Parity refers to the bitting depths, "odd" or "even" numbers. In an alternating parity system, the bitting depths in any given bitting position can be odd or even numbered depths; sometimes called a "one-step" system.
Americans with Disabilities Act:
This is a US federal law dealing with minimum standards of building accessibility, as well as other issues affecting individuals with disabilities.
Annunciator:
A device that produces an audible and/or visible indication of light and/or noise, or a verbal message.
ANSI/BHMA:
U.S. builders-hardware standards developed by the Builders Hardware Manufacturers Association and approved through ANSI; grade and product standards cover locks, cylinders, closers, and related hardware.
See also: High Security Locks, Deadbolt
Anti-friction Latch:
A device incorporated into the latch bolt of a lock for reducing friction between bolt and strike.
Anti-Passback:
A security feature in electronic access control systems that prevents a card or token from being used to enter an area a second time without first exiting, ensuring proper tracking of individuals through controlled areas.
See also: Access Control
Anti-Snap Cylinder:
A euro-profile cylinder designed so a sacrificial break point fails under snap attack while the outer/cam side remains secure.
See also: Euro Cylinder
Anti-thrust bolt:
A spring bolt, for a night latch particularly, which cannot be pushed back when it has shot out and fastened a door, although it can be withdrawn by knob or key. This security device is usually achieved by a dog inside the latch case which falls behind the bolt and keeps it shot out when an auxiliary slide is pushed in.
Anti-thrust plate:
An overlapping metal plate fitted to outward opening doors so as to prevent access to lock bolts.
Astragal (Overlapping & Interlocking):
A set of vertical mouldings that extend the full height of the door and is fastened to a door and jamb or a pair of doors that interlock for increased security from a forced entry attack.
Astragal (Overlapping):
A vertical moulding that extends the full height of the door leaf and is applied to a door or pair of doors at their meeting edges. The astragal closes the clearance gap for the purpose of providing a weather seal, minimizing the passage of light between the doors, retarding the passage of smoke and flame during a fire, or maintaining security. Some types of astragals are flat pieces of aluminum, steel, or wood. Some astragals are designed to wrap around the lock stile of the door. Overlapping astragals are not permitted to be used on pairs of doors that are required to swing in the direction of egress travel.
Astragal (Split):
A vertical molding attached to the meeting edges of each of the leaves of a pair of doors, for protection against weather. The split feature permits both leaves to be active. Split astragals can be surface-mounted, semi-mortised or full-mortised in the vertical edge of the doors. Split astragals are available with brush, pile, silicone, neoprene, or vinyl inserts to seal the gap between the meeting stiles in pairs of doors.
Audit Trail:
Logged records of access events (who/when/where) produced by electronic access or smart-lock systems.
See also: Access Control, Smart Locks
Auto-Relock:
A feature that automatically returns a lock to locked state after a door closes or a timer expires.
See also: Smart Locks, Latch
Automatic Deadlatch:
A deadlatch, the main bolt of which is automatically locked (or deadlocked) when the door is closed.
B
Back Check:
The resistance provided by a door closer as the door is opened.
Backplate:
The plate, fixed on 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".
Backset (US Bored):
In North American bored locks, commonly the distance from the door edge to the center of the cross bore (often 2-3/8 in. or 2-3/4 in.).
See also: Deadbolt
Barrel Bolt:
The common kind of door bolt having a round shoot running in a long continuous guide or strap attached by the backplate, the shoot being provided with a knob or the equivalent for operation by hand.
Barrel Key:
A pipe/hollow key that fits over a pin in the keyhole, historically common on warded cabinet and trunk locks.
See also: Warded Lock
Barrier-free:
Refers to ensuring accessibility for seniors and people with disabilities.
Bell Crank:
A mechanical device using a pivoting action to change the direction of a mechanical force or motion.
Berlin Key:
A double-bitted forced-locking key (Schließzwangschlüssel) that must be pushed through the lock and used to relock from the far side before it can be removed — associated with Berlin tenements and patented/produced via Kerfin/Schweiger around 1912.
See also: Berlinkey
Bevel (of a door):
The pitch on the leading edge of a door that allows clearance for closing.
Bevel (of a lock):
The pitch of the face designed to match the bevel of a door. Some locks have an adjustable bevel.
Bezel:
A threaded collar commonly used to secure certain cylinder or lock assemblies.
BHMA:
(abbr.) Builders Hardware Manufacturers' Association
Bible:
The portion of the cylinder shell that normally houses the pin chambers, especially those of key-in-knob cylinders or certain rim cylinders.
Binary-type Cylinder or Lock:
A cylinder or lock with a combination that only allows for two bitting possibilities in each position.
Biometric Lock:
A lock or reader that uses a biological trait (fingerprint, face, iris, etc.) as a credential factor.
See also: Biometric Locks
Birmingham Bar:
A steel bar fitted to the inside face of a door frame on the hinge side.
Bit:
The part of the key that serves as the blade; usually for use in a warded or lever tumbler lock.
Bitting:
The number(s) that represent(s) the dimensions of the key cuts OR the actual cut(s) or combination of the key.
Bitting Chart:
A written or digital record of cut depths by chamber position for keys and pins in a system.
See also: Key Cutting
Blade (Key):
The portion of the key that enters the keyway and carries the bitting.
See also: Key Cutting
Blade Key:
The mechanical metal blade of a vehicle key, which may be paired with a separate transponder head or integrated electronics.
See also: Smart Key, Key Cutting
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.
Bolt Stump:
A rectangular part in lever tumbler locks located above the talon, passing through the slot in the levers as the bolt moves.
Bolt Throw:
The distance a deadbolt extends when locked; residential guidance often cites about one inch into a solid strike/frame path.
See also: Deadbolt
Bow:
Already live as Bow (of a key) — the handle portion of a key.
Bow (of a key):
That part of the key which is held in the fingers when operating the lock or latch.
Box Strike:
A strike with a reinforced dust box that supports the bolt and spreads force better than a thin plate alone.
See also: Deadbolt
Bramah Lock:
A high-security slide/wafer lock patented by Joseph Bramah in 1784, famous for a long-running challenge lock later opened by A. C. Hobbs in 1851.
See also: Bramah Lock, Joseph Bramah, Alfred Hobbs
Bridge / Hub (Smart Lock):
A gateway device that connects a Bluetooth lock to Wi-Fi/cloud services.
See also: Smart Locks
Bump-Resistant:
Pinning or cylinder features intended to reduce vulnerability to key bumping.
See also: Key Bumping, Security Pins
Bypass:
Opening a locked door by attacking something other than the pin/disc combination itself (for example, latch geometry or mounting flaws). Definition only.
See also: Bypass
C
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 (Euro/Profile):
On profile cylinders, the rotating bit that engages the lock case to throw or retract the bolt.
See also: Euro Cylinder, Cam Lock
Cam Lock:
A complete locking assembly in the form of a cylinder whose cam is the actual locking bolt.
Card Reader:
A device that reads magstripe, proximity, smart-card, or similar credentials for an access system.
See also: Card Reader
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 more lights are hinged to open.
Challenge Lock:
A publicly displayed lock offered with a prize for anyone who can open it without the key; Bramah’s Piccadilly challenge is the best-known example.
See also: Bramah Lock
Change Key:
A change key which is related directly to particular master key(s) through the use of constant cuts.
Change Key (Safe Deposit):
In safe-deposit contexts, the renter’s key that works only with the guard key.
See also: Safe
Chubb Detector Lock:
A lever lock refinement by Jeremiah Chubb (1818) that indicates or resists tampering via a detector mechanism.
See also: Jeremiah Chubb, Lever Tumbler Lock
Classroom Function:
A lock function where the outside lever can be locked/unlocked by key while inside remains free for egress — one of many standardized function families.
See also: Mortise Lock
Closed Shackle:
See live Closed Shackle Padlock — minimal exposed shackle when locked.
See also: Padlock
Closed 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.
Code Cutting:
Originating a key from a published or decoded bitting code rather than copying an existing key.
See also: Key Cutting, Decoding
Comb Pick:
A tool shaped to lift multiple pins above the shear line in some poorly pinned cylinders; countered by proper pinning and tolerances.
See also: Comb Pick
Combination Lock:
An abbreviation of a name for a keyless combination lock. Cut cabinet lock A cupboard or drawer lock, the flange of which is recessed into the edge of the drawer or door.
See also: Combination Lock
Constant Cuts:
Bitting positions held identical across related keys in some master-key design methods.
See also: Master Keying
Construction Keying:
Temporary keying used during building construction so builder keys work until permanently disabled or changed at occupancy.
See also: Construction Keying
Control Key:
A special key that retracts the retaining lug of an interchangeable core so the core can be removed from the housing.
See also: Interchangeable Core
Controlled Egress:
Code-related locking arrangements for certain occupancies where egress is controlled under strict rules (distinct from ordinary free egress).
See also: Access Control
Credential:
Whatever proves identity or entitlement to an access system — key, card, fob, code, phone token, or biometric template reference.
See also: Access Control
Cross Bore:
The large hole bored through the face of a door to accept a cylindrical lock or deadbolt chassis (commonly 2-1/8 in. in North America).
See also: Deadbolt
Cruciform Key:
A cross-shaped key section used in some European and specialty cylinders.
See also: Dimple Lock
Cylinder:
Usually the cylinder with an 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 flat key for pin-tumbler cylinders, as distinct from bit/skeleton keys for lever or warded locks.
See also: Pin Tumbler Lock
D
Deadbolt:
The square-ended bolt of a lock which is moved in both the locking and unlocking directions by the key (but occasionally by thumb turn inside only) to provide fastening. N.B. For obvious reasons, it is inadvisable to incorporate the thumb turn with the deadbolt of any deadlock or lock which is supposed to offer good security, if used on glass or wood panelled doors.
Deadlatch:
A nightlatch or latch, the springbolt of which can be locked (or deadlocked) by key or other means.
Deadlock:
A lock having only a square-ended deadbolt operable from one or both sides by key, and occasionally from outside only by key, inside by thumb turn. Sometimes operable only from outside and with no inside keyhole, which is designated a single-entry deadlock.
Deadlocking Latch:
A latch that automatically deadlocks when the door is closed so it cannot be slipped back by a card or similar tool.
Decoding:
Determining a lock’s combination by measurement or reading of components so a key can be originated without the original key.
See also: Decoding
Delayed Egress:
A life-safety locking arrangement that delays exit for a short timed period while alarming, allowed only under specific code conditions.
See also: Access Control, Panic Hardware
Depth Increment:
The step size between consecutive bitting depths in a manufacturer’s system.
See also: Key Cutting
Detainer:
1. A generic term, not widely used, for any part such as a lever or tumbler which keeps a lock bolt in position 2. The name of the sliding security members in Butter's System locks.
Differs:
An abbreviation of "different combinations" or changes.
Dimple Lock:
A cylinder whose key has milled dimples on the face rather than edge bitting; pins typically approach the key perpendicular to the blade.
See also: Dimple Lock
Disc Detainer:
A rotating-disc mechanism (associated with Abloy-style locks) in which discs must turn to a gated position before a sidebar or bar can release.
See also: Disc Detainer
Disc Tumblers:
The small shaped discs (usually of metal) in the disc tumbler mechanism which are the means of providing different combinations.
Dogging (Exit Device):
Holding an exit device’s latch retracted for push/pull traffic during business hours.
See also: Panic Hardware
Door Closer:
A device for closing a door or gate automatically after opening. There are numerous types available.
Door Prep:
The holes and cavities cut in a door and frame for a given lock function (cross bore, edge bore, mortise pocket, strike cutout).
See also: Deadbolt, Mortise Lock
Door Reinforcement Wrap:
Aftermarket plates that wrap the lock stile to resist kick-in around the bore.
See also: Deadbolt
Door Viewer:
Optical device fitted through a door to enable observation without opening the door.
Double Bitted Key:
One with a bit on each side of the shank.
Double-Acting Lever:
A lever design in which both under-lifting and over-lifting block bolt travel, requiring precise key heights (associated with Barron’s 1778 patent principle).
See also: Robert Barron, Lever Tumbler Lock
Double-Cylinder Deadbolt:
A deadbolt keyed on both sides; can limit reach-through attacks near glass but may conflict with egress codes on some exits.
See also: Deadbolt
Double-handed Lock:
1. 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. 2. A cupboard lock, the bolt of which can be shot either way to protrude from either side of the case.
Drill-Resistant:
Design features (hardened inserts, rotating pins, sacrificial hardplate) intended to slow drilling attacks on cylinders or safes.
See also: High Security Locks, Safe
Driver Pin:
The upper (spring-side) pin in a pin-tumbler stack; without the correct key it bridges the shear line and prevents the plug from turning.
See also: Pin Tumbler Lock
Duplication:
Cutting a key to match an existing key’s bitting, subject to key-control rules for restricted sections.
See also: Key Cutting, Key Control
E
Edge Bore:
The hole bored into the door edge for the latch or bolt tube (commonly 1 in. for many residential tubular locks).
See also: Deadbolt
Electric Strike:
An electrically releasable strike/keeper that can allow a latch to pass when powered (or when power is removed), depending on fail-safe vs fail-secure configuration.
See also: Access Control, Latch
Electromagnetic Lock (Maglock):
A fail-safe lock that holds a door by energizing an electromagnet against an armature plate; removing power releases the door unless backup power is designed to keep it held.
See also: Electromagnetic Lock
EN 1303:
European standard for lock cylinders (and, in newer revisions, master-key systems), classifying durability, corrosion, key-related security, and attack resistance.
See also: Euro Cylinder
Entry Function:
A common residential/commercial function with keyed outside locking and inside free egress.
Escutcheon:
The cover for the keyhole of a mortise or similar lock.
Euro Cylinder:
A modular profile cylinder common in Europe that slides into a sash lock case and is retained by a center screw; available in single, double, and thumb-turn variants.
See also: Euro Cylinder
Exit Device:
Another name for panic/crash-bar hardware used on egress doors.
See also: Panic Hardware
F
Face Plate:
The outer of a double forend. A strip of metal fixed to the inner forend, thus forming a double forend.
Fail-Safe:
A locking mode that unlocks on power loss (typical of maglocks), prioritizing egress/life safety during outages.
See also: Electromagnetic Lock
Fail-Secure:
A locking mode that remains locked on power loss (common for some electric strikes), prioritizing security during outages.
See also: Access Control
False Set:
A temporary binding feel during picking when a security pin catches at the shear line without the plug being free to turn.
See also: Security Pins
Figure-Eight Core:
The characteristic cross-section shape of small-format interchangeable cores (SFIC).
See also: Interchangeable Core
Final Exit Door:
The exit door through which entry must later be obtained, and so cannot be bolted. It is usually the front entrance door or final means of exiting.
Fire Door:
A door assembly rated to resist fire for a specified duration; hardware must be listed for the assembly.
See also: Panic Hardware, Mortise Lock
Fire Exit Hardware:
Exit devices listed for use on fire door assemblies, meeting both panic and fire-door requirements.
See also: Panic Hardware
Firmware (Smart Lock):
Software on the lock/bridge that should be updated to address bugs and security issues.
See also: Smart Locks
Flush Bolt:
A door bolt which can be recessed flush into the edge or face of a door.
Forensic Locksmithing:
Examination of locks and keys for tool marks and attack evidence to support investigations.
See also: Forensic Locksmithing
G
Glass Relocker:
A relocking device triggered when tempered glass plates shatter under attack, releasing additional bolts.
See also: Safe
Grade 1 / Grade 2 / Grade 3:
Common ANSI/BHMA performance tiers for many commercial lock products, with Grade 1 typically the highest durability/security test level. Exact cycle and strength numbers depend on the specific A156 standard and product type (bored lock, mortise, cylinder, deadbolt, etc.).
See also: Deadbolt, High Security Locks
Grand Master Key:
A key at a higher hierarchical level that operates multiple master-keyed groups within a larger system.
See also: Master Keying
Graphite Lubricant:
Dry graphite is the conventional lubricant recommended for pin-tumbler cylinders; liquid oils can gum and attract dirt inside pin chambers.
See also: Pin Tumbler Lock
Group 1 / Group 2 Safe Lock:
Industry ratings for mechanical safe locks describing manipulation resistance categories (commonly associated with UL safe-lock classifications).
See also: Safe, Combination Lock
Guard Key:
The attendant/bank key that must be used with a renter key on dual-control safe-deposit locks.
See also: Safe
Guest Code:
A temporary keypad credential issued for visitors or deliveries on electronic locks.
See also: Smart Locks
H
Hardened Insert:
A drill-resistant steel component placed in a cylinder or bolt to resist drilling attacks.
See also: High Security Locks
Hasp and Staple:
A fastening in two pieces for a door or box to be secured by a padlock. The hinged part is called the hasp which is fitted to the door or lid of a box and shuts over the staple, which is on the door frame (or other leaf of a pair of doors) or the body of the box. For real security it is essential to use a hasp and staple with concealed fixing, i.e. the heads of the fixing screws are completely covered when the padlock is locked in position, as otherwise the fitment can easily be removed by withdrawing the screws affording nil security.
Heel and Toe Locking:
Padlock designs that bolt both ends of the shackle independently for higher resistance to prying.
See also: Padlock
Hinge Bolts:
Fixed steel protrusions fitted into the rear edge or hinge side of doors, closing into holes cut into the door frame, to protect from a forced attack on the hinge side of the door.
Hinge-Side Security:
Methods such as hinge bolts/studs that resist removal of the door if hinge pins are attacked.
See also: Deadbolt
Hook Bolt:
A pivoted spring-bolt, the head of which is shaped in the form of a hook. Such locks or latches are usually fixed on sliding doors.
I
IBC:
International Building Code — a model building code widely adopted in the U.S., including means-of-egress provisions that affect locking.
See also: Panic Hardware
IC Housing:
The lock chassis or rim/mortise housing that accepts an interchangeable core.
See also: Interchangeable Core
Immobilizer:
A vehicle security system that prevents engine start unless a valid electronic token is present.
See also: Smart Key
Impression Marks:
Witness marks left on a blank during impressioning that indicate where material must be filed.
See also: Impressioning
Impressioning:
A trade method of originating a working key by marking and filing a blank from feedback in the lock — discussed here as a concept, not a procedure.
See also: Impressioning
Incidental Master Key:
An unintended key bitting that operates a lock due to progression mathematics — a known risk to manage in master-key system design.
See also: Master Keying
J
Jamb:
The vertical member of a door or window frame. In some areas, the top rail of a door frame is referred to as the top jamb.
K
Kensington Lock:
A small security-cable attachment standard widely used to tether laptops and other equipment.
See also: Kensington Lock
Key Blank:
An uncut key with the correct bow and keyway section, ready to be cut to a bitting.
See also: Key Cutting
Key Bumping:
A covert-entry technique against many pin-tumbler locks using a specially cut bump key and impact to momentarily separate pin stacks at the shear line. Public attention rose in the mid-2000s after research publications and media coverage.
See also: Key Bumping
Key Coding:
Assigning and recording bittings and stamping keys/locks so a system can be maintained and audited.
See also: Key Control, Key Cutting
Key Control:
Policies and hardware (restricted blanks, authorization cards, audit trails) that limit who may duplicate keys.
See also: Key Control
Key Pin:
The lower pin in a pin-tumbler stack that contacts the key bitting; its length varies by cut depth.
See also: Pin Tumbler Lock
Key Section:
The cross-sectional shape of a key blade that must match a keyway family.
See also: Key Control
Key Steps or Key Depths:
This term usually means the bolt step and lever steps of a key for a lever lock.
Keyed Alike (KA):
Multiple locks operated by the same key bitting for convenience.
See also: Master Keying
Keyed to Differ (KD):
Locks each operated by a unique change key, with no shared bitting between them.
See also: Master Keying
Keyway:
The shaped opening in a cylinder plug that accepts a key blade; wards and profiles in the keyway help reject wrong key sections.
See also: Pin Tumbler Lock, Key Control
L
Laminated Padlock:
A padlock body built from stacked steel plates — popularized in mass-market designs associated with Harry Soref / Master Lock history.
See also: Padlock, Harry Soref
Latch:
The type of product with one bolt only, the bevelled springbolt or roller bolt, to latch or fasten the door, but not capable of being locked. Certain types, e.g. locking latches, nightlatches, or deadlatches, can, however, be locked by key or other means.
Latchbolt Throw:
The distance a latch extends into the strike; longer throws and proper strike engagement improve security.
Lever:
A flat shaped movable detainer in a lock, usually for the purpose of providing security and differs. 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.
Lever and Warded Mechanism:
The lever mechanism with the addition of wards, usually for providing a greater number of differs. The addition of wards does not, however, increase the security of a lock. See "Wards".
Lever Handle:
A piece of lock or latch furniture, usually on a rose or plate, for use as an alternative to a knob for operating the springbolt of a lock or latch. All British lever handles are spring-loaded to ensure the return to horizontal after use, but Continental lever handles are not usually spring-loaded and thus when used with British locks or latches, sometimes tend to sag below the horizontal after a comparatively short period of use, unless additional springing is included in the lock action.
Lever Mechanism:
A lock mechanism having, as its principle feature, one or more levers.
Lever Tumbler:
A lock mechanism using pivoted levers with gates; the correct key lifts each lever to align gates with a fence or stump so the bolt can move.
See also: Lever Tumbler Lock, Robert Barron
LFIC:
Large Format Interchangeable Core — a larger interchangeable-core family used by various manufacturers, removed with a control key.
See also: Interchangeable Core
Lock:
A device operated usually, but not always, by a key, having one or more bolts or other members to fasten and secure a door, lid, drawer or other member.
Lockable Bolt:
A bolt that can be shot and locked in position by the use of a removable key.
Locking Latch:
A latch with a bevelled springbolt or roller bolt which is capable of being locked or secured, usually by key.
Lockout:
A condition where no working key is available; resolved by origin of a new key, destructive entry, or bypass of hardware — context dependent.
See also: Rekeying Locks
Lockset:
A lock complete with necessary furniture including a spindle, ready for fixing to the door.
Lockset Furniture or Lock Furniture:
A lockset, minus the lock.
Locksport:
Recreational and competitive lock picking practiced as a hobby/sport, typically with an ethic of owning locks and responsible disclosure.
See also: Locksport, Lock Picking History
Locksport Ethics:
Community norms emphasizing picking only locks you own/are authorized to pick and responsible disclosure of vulnerabilities.
See also: Locksport
Loiding:
Bypassing a spring latch by slipping a thin tool between door and frame — the origin of the “credit card” myth — typically stopped by deadlocking latches and deadbolts.
London Strip:
A steel bar fitted to the inside face of a door frame, shaped to accommodate the staple or striker of a rim latch lock.
Long Shackle (LS):
A padlock shackle with a greater amount of clearance than the normal standard shackle.
Lubrication:
On no account should oil be used to lubricate pin-tumbler cylinders. Graphite is the conventional lubricant for this mechanism.
M
MACS:
Maximum Adjacent Cut Specification — the largest allowed depth difference between neighboring cuts so the key remains manufacturable and insertable.
See also: Key Cutting
Magnetic Pin Lock (Mechanical):
A mechanical lock using magnetic tumblers attracted/repelled by a magnetic key — distinct from powered electromagnetic door holders (maglocks).
See also: Magnetic Lock
Magstripe:
A magnetic stripe credential technology still found on some older access and hotel systems.
See also: Card Reader
Manipulation (Safe):
Opening a combination lock by decoding feel/sound of wheels without destructive drilling — historical trade/adversarial skill; definition only.
See also: Safecracking, Safe Cracking History
Master Key:
A master key that has particular change keys related directly to its combination via the use of constant cuts.
Master Keyed (Locks or Latches):
A lock or latch capable of being operated also by a master key as well as its own change or servant key.
Master Keying:
A keying hierarchy in which change keys open individual locks while master keys open defined groups, usually by adding extra shear points (master wafers) in pin stacks.
See also: Master Keying
Master Wafer:
A thin spacer pin that creates an additional shear point in a pin stack so more than one key bitting can operate the lock.
See also: Master Keying
Matter (Standard):
A newer smart-home interoperability standard intended to ease cross-brand device integration, including locks over time.
See also: Smart Locks
Medeco:
Brand/mechanism family known for angled cuts and sidebar-style high-security pin cylinders.
See also: Sidebar Lock, High Security Locks
Milling (Keyway):
The longitudinal grooves cut into a key blade to match keyway wards.
See also: Key Control
Mortise:
A hole cut into the thickness of one edge of a door to receive a mortise lock or latch.
Mortise Key:
A key to operate a lever lock, consisting of a bow, shank and bit.
Mortise Lock (or Latch):
A lock or latch which is mortised or let into the thickness of the door from the meeting edge and held in position by screws.
Multi-Factor Authentication (Locks):
Requiring more than one credential factor (something you have/know/are) to unlock — increasingly common on smart and commercial systems.
See also: Smart Locks, Access Control
Multiplex Keyway:
A family of related key sections in which some blanks enter only specific keyways while an all-section blank can enter all members of the family.
See also: Key Control, Master Keying
Mushroom Pin:
A security pin with an undercut head that can bind at the shear line when manipulated, similar in purpose to a spool pin.
See also: Security Pins
N
NFC:
Near Field Communication — a short-range radio standard used by some phones and credentials for access and payment interactions.
See also: Rfid Locks, Smart Locks
NFPA 101:
Life Safety Code published by NFPA, influential on egress and door-locking rules in many jurisdictions.
See also: Panic Hardware
Night Latch:
A spring-latch lock (rim or mortise) that latches when the door closes and is usually retracted by key outside and knob/lever inside; often includes a snib.
Nightlatch:
A rim or mortise latch with a bevelled springbolt or roller bolt which shoots when the door is closed, but can be withdrawn by key from outside and by knob or lever handle from inside. Usually provided with a stop knob, slide or snib to hold the bolt retracted and to deadlock the bolt when shot in the closed position, even against the action of the key.
O
OBD Key Programming:
Automotive trade practice of writing keys/fobs via the vehicle diagnostic port; definition-level only — procedures vary by make and are out of scope here.
See also: Smart Key
One-sided Lock (Single-entry):
A lock which has a keyhole on one side only, so that it can be operated by key from one side only, usually outside, but not from both. Nearly all cabinet locks and all padlocks are examples. Some high quality cylinder mortise locks are one-sided.
One-Step Progression:
A master-key progression method (related to alternating parity) in which adjacent depths differ by one increment.
See also: Master Keying
One-way Action:
An action where the follower will turn only one way.
P
Padlock:
A comparatively small removable and portable locking device, usually but not always key operated on one side only. The locking member is a circular hinged sliding or swivelled shackle which passes through a hole in a staple, locking bar or similar member.
Padlock Grades:
Informal/consumer and standards-based ratings for padlock security; compare like-with-like using the cited standard rather than marketing language alone.
See also: Padlock
Panel Grilles:
Steel grilles made to size with various infills of expanded diamond mesh, square weld mesh or fancy infills, usually fitted internally.
Panic Hardware:
Exit devices (crash bars) that unlatch an egress door by pushing along the bar, balancing security from the outside with free egress inside.
See also: Panic Hardware
Paracentric Keyway:
A keyway milled with overlapping wards that extend past the centerline, complicating simple picking tools.
See also: Pin Tumbler Lock, High Security Locks
Passive Keyless Entry:
Vehicle systems that unlock or enable start when an authorized fob is in range without pressing buttons on the fob.
See also: Smart Key
Pick Gun:
A tool that delivers rapid vibration/impacts to pin stacks; historically used in trade and discussed in locksport literature — definition only here.
See also: Pick Gun
Pick-Resistant:
Marketing/engineering claim that a cylinder resists common picking methods; meaningful comparison usually requires a cited standard (e.g., UL 437) rather than the label alone.
See also: High Security Locks, Security Pins
PIN Pad:
A keypad for entering personal identification numbers as a knowledge factor in access control.
See also: Access Control, Smart Locks
Pin Tumbler:
A lock mechanism in which spring-loaded pin stacks block a rotating plug until a correctly cut key lifts each stack so a gap aligns at the shear line.
See also: Pin Tumbler Lock, Linus Yale
Pinning Kit:
A locksmith assortment of pins by size used to rekey and master-key cylinders.
See also: Rekeying Locks
Plug:
The part of the pin-tumbler cylinder mechanism or disc tumbler cylinder mechanism into which the key enters and which the key turns. It houses the pins of a pin tumbler cylinder mechanism or the discs and springs of a disc tumbler cylinder mechanism.
Plug Pulling:
An attack that attempts to extract the cylinder plug from the shell; high-security cylinders are tested against related forces in standards such as UL 437 / BHMA security tests.
See also: High Security Locks
Privacy Function:
A lockable latch typically for bathrooms/bedrooms, often with emergency outside release.
See also: Latch
Proximity Card:
A contactless credential read at a short distance by a reader, common in building access systems.
See also: Card Reader, Access Control
Proximity Fob:
A handheld RF credential that allows keyless entry or push-button start when near the vehicle.
See also: Smart Key
Puzzle Lock:
A lock that requires solving a mechanical puzzle (sliding pieces, hidden releases) rather than a conventional key alone — historically associated with Chinese and Indian traditions among others.
See also: Puzzle Lock, Chinese
Q
R
Rack Bolt:
A bolt, usually a door bolt, which is toothed so that it may be operated by a pinion.
Raking:
A picking approach that scrubs pins with a rake-shaped tool while tension is applied; a trade/locksport term defined without instructional steps.
See also: Raking, Lockpicking
Rebate:
The measurement of the stepped reduction or recess in the forend of a rebated lock.
Rebated (Lock or Latch):
A mortise lock or latch with a forend specially shaped to correspond with the shaped meeting edge of the door for which it is intended. See "Full Rebated".
Rekeying:
Changing a lock’s internal combination (pins/wafers) so previous keys no longer work, usually without replacing the entire lock body.
See also: Rekeying Locks
Relay Attack (Automotive):
A theft technique that extends the radio range of a key fob; relevant as a threat category for proximity systems — not documented as a how-to here.
See also: Smart Key
Release:
A striker in various forms to replace the lock strike and is operated electronically.
Relocker:
A safe/vault feature that permanently (or until reset) locks additional bolts if the lock is punched or attacked.
See also: Safe, Safecracking
Request to Exit (REX):
A sensor or switch (PIR, bar, pushbutton) that signals an access system to release a lock for authorized egress.
See also: Access Control, Panic Hardware
Responsible Disclosure:
Reporting security vulnerabilities privately to vendors/owners before public release, a norm in locksport and security research.
See also: Locksport, Forensic Locksmithing
Restricted Keyway:
A key section whose blanks are controlled by contract or patent so unauthorized duplication is limited.
See also: Key Control, High Security Locks
RFID Lock:
A lock or reader that authenticates a credential using radio-frequency identification (cards, fobs, or tags) at short range.
See also: Rfid Locks, Card Reader
Rigid Grilles:
Heavy duty, welded construction, rod or bar grilles, usually fitted externally or internally to the fabric of a building.
Rim Cylinder:
This relates to a pack which usually comprises the cylinder with plug, rose, connecting bar, two connecting screws and two keys.
Rim Lock or Latch:
A lock or latch that is fitted by screwing on to the inside face of the door.
Root Depth:
The remaining blade height at a cut; related to how deep a cut is milled.
See also: Key Cutting
Rose (Lock):
A circular trim plate surrounding a knob, lever, or cylinder on the door face.
See also: Mortise Lock
S
Safe Deposit Lock:
A dual-control lock requiring both guard and renter keys, used on safe-deposit boxes.
See also: Safe
Sash Lock:
An upright mortise lock, consisting of a latch bolt and a key operated bolt.
Sash Lock (Mortise):
An upright mortise lock combining a latch bolt and a key-operated deadbolt in one case — terminology common in UK hardware.
See also: Mortise Lock
Sash Ward:
Used in rim and mortise locks, alone or in conjunction with levers for the purpose of obtaining or increasing the differs. Formed pieces of concentric metal are affixed around the inside of the keyhole. It also serves as a keyhole bush. The bitted key passes over these wards to operate the bolt. Little security is given when sash wards are used by themselves. See "Skeleton Keys".
Security Pin:
A specially shaped driver or key pin (such as spool, mushroom, or serrated) designed to create false sets and resist simple picking tools.
See also: Security Pins, Pin Tumbler Lock
Serrated Pin:
A pin with grooves that can catch on the shear line or plug edges during picking attempts.
See also: Security Pins
SFIC:
Small Format Interchangeable Core — a figure-eight core standard that can be removed with a control key for rapid rekeying without disturbing the lock body.
See also: Interchangeable Core, Rekeying Locks
Shackle:
The hinged, sliding or swivelling loop shaped member of a padlock. The heel of the shackle remains always in the padlock body and the toe of the shackle comes out when unlocked. A double locking padlock gives the greatest security against forcing because there are two separate bolts locking outwards in opposite directions, one into a niche in the heel of the shackle, and the other into the toe of the shackle. This is sometimes called heel and toe locking.
Shear Line:
The term is used to denote the line of the circumference of the plug in the bore of a pin tumbler cylinder.
Shear Line (Extended):
See Shear Line in live glossary — the circumferential interface between plug and shell where pin gaps must align for rotation.
See also: Pin Tumbler Lock
Shoulder (Key):
The stop on a key that indexes how far it inserts into the plug.
See also: Key Cutting
Shrouded Shackle:
A padlock body that shields most of the shackle from bolt cutters.
See also: Padlock
Side Wards:
Notches cut into the sides of bitted keys so fashioned to enable the key to turn.
Sidebar:
A secondary locking bar in some high-security cylinders that must retract—often via special key cuts or side pins—before the plug can turn.
See also: Sidebar Lock, High Security Locks
Sidebar Lock:
A cylinder that uses a sidebar as a critical locking element in addition to or instead of a simple pin shear line.
See also: Sidebar Lock
Single-Cylinder Deadbolt:
A deadbolt with a key cylinder outside and a thumb turn inside.
See also: Deadbolt
Skeleton Key:
A simplified bit key cut away to bypass many ward patterns; historically effective against simple warded locks.
See also: Warded Lock
Sliding Grilles:
Steel sliding grille gates in single or double leaf, running on top and bottom guide tracks, locked by padlock or integral lock.
Sliding Lever:
A lever which slides between or on guides instead of swinging on a pivot.
Smart Card:
A credential with an embedded chip (contact or contactless) used for secure authentication.
See also: Card Reader, Rfid Locks
Smart Lock:
A lock that adds electronic credentials (codes, phones, fobs) and often network connectivity to a mechanical bolt or latch, typically retaining a key override.
See also: Smart Locks
Spindle:
That part of the door furniture usually of square section which passes through the follower hole and is fitted to the knob(s) or lever handle(s) to operate the springbolt.
Spool Pin:
A security driver pin with a reduced-diameter midsection that can catch at the shear line during manipulation, producing a false set.
See also: Security Pins
Spring Shackle Padlock:
A padlock, the shackle of which springs open when unlocked, and is locked by snapping to.
Springbolt:
Sometimes called the latchbolt. A bolt having the outer edge shaped by bevelling of the vertical face. It is a bolt which may be pushed back into the lock-case and will return to the extended position without mechanical assistance.
Staple:
1. A box-like fitting on the jamb of an inward opening door, and into which the bolt or bolts of a rim latch or lock shoot when door is closed. (It is sometimes referred to in Scotland and the North of England as a Bosshead). Some staples are lipped to act as a guide for the springbolt. 2. Part of a hasp and staple for use with a padlock. The padlock shackle passes through the eye or hole in the staple.
Stop Knob (Snib):
A device incorporated in some latches and locking latches to hold the bolt retracted or deadlock the bolt when door is closed.
Storeroom Function:
A lock function where the outside lever is always locked and requires a key, while inside allows free egress.
See also: Mortise Lock
Strike Reinforcement:
Hardware or longer screws that anchor a strike plate into framing rather than trim alone, improving kick-in resistance.
See also: Deadbolt
Striking Plate:
Sometimes referred to as a "striker". It is a shaped flat metal plate fixed to the door frame or jamb with one or more bolt holes into which the bolt or bolts shoot. There is a shaped projecting lip on one side to guide the springbolt. It is used with all mortise locks or latches, and with rim locks or latches with reversed springbolt on an outward opening door.
Suite (of Locks):
A group or collection of locks and/or locking latches and padlocks of different types and changes incorporated together under a master key or grand master key.
T
Tailpiece:
The connecting piece from a rim or bored cylinder to the lock mechanism that transmits rotation to throw the bolt or cam.
See also: Pin Tumbler Lock, Rim Lock
Thumb Turn:
A small fitting, on the inside of a mortise lock, which is gripped between thumb and finger to operate the deadbolt. It should not be used on glass- or wood-panelled doors.
Thumb Turn Cylinder:
A cylinder with a keyway on one side and a thumb turn on the other (common euro half+turn configurations).
See also: Euro Cylinder, Deadbolt
Tie Bars:
The horizontal members of a vertical bar grille.
Time Lock:
A clockwork or electric timing device which disallows operation of a lock or the opening of a door on safes or strongrooms.
See also: James Sargent, Time Lock
Tip Stop:
A key that indexes from the tip rather than the shoulder when inserted.
See also: Key Cutting
Transponder Key:
A vehicle key containing a RFID/transponder chip that the immobilizer must authenticate before the engine will start.
See also: Smart Key
Trap Pin:
A pinning feature intended to seize or disable a cylinder after unauthorized rotation/attack; service implications vary.
See also: Key Bumping, High Security Locks
Tubular Lock:
A radial pin-tumbler design operated by a round tubular key, often used on vending equipment, bike locks, and some cabinets.
See also: Tubular Lock
U
UL 1034:
UL Standard for Burglary-Resistant Electric Locking Mechanisms, commonly referenced for electric strikes, maglocks, and similar devices.
See also: Electromagnetic Lock, Access Control
UL 294:
UL Standard for Access Control System Units, covering many electronic access-control panels and related equipment.
See also: Access Control
UL 437:
UL Standard for Key Locks — a high-security test standard often cited for cylinders resistant to picking, drilling, and related attacks.
See also: High Security Locks
Ultrasonic Sensor (Access):
Sensing technology using sound waves; niche applications appear in some security/access devices.
See also: Ultrasonic Transducers
V
VATS:
Vehicle Anti-Theft System — a GM resistor-pellet key system from the late 1980s/1990s era preceding modern transponders.
See also: Smart Key
W
Wafer Tumbler:
A flat tumbler used in many cam, cabinet, and automotive locks; wafers align to a shear line when the correct key is inserted.
See also: Wafer Lock
Warded Lock:
Any lock or padlock, the mechanism of which makes use only of wards. Not recommended, due to the lack of security.
See also: Warded Lock
Wards:
Fixed obstructions inside a lock case to preclude the use of the wrong key, as the key is cut to pass over the wards and operate the lock. They are sometimes used in lever locks to give increased differs. Wards alone give very little security. See "Skeleton Key".
Wiegand:
A signaling interface historically common between card readers and access-control panels; also refers to an older card technology using Wiegand-effect wires.
See also: Access Control, Card Reader
X
Y
Yale (Generic):
In some languages/markets, “Yale” is used generically for pin-tumbler cylinder locks, reflecting the historical dominance of the Yale design.
See also: Linus Yale, Pin Tumbler Lock
Z
Z-Wave:
A low-power mesh radio protocol used by some smart locks and home-automation devices.
See also: Smart Locks
Zigbee:
A low-power mesh radio protocol used in some smart-home lock and sensor ecosystems.
See also: Smart Locks