Welcome to the most complete locksmith glossary on the web. Whether you’re a homeowner trying to understand a quote, a property manager speccing hardware, a car owner who just heard the phrase “all keys lost,” or a curious DIYer, this dictionary explains the language of locks, keys, and security in plain English. We built it because the locksmith trade is full of jargon — ANSI grades, MACS, transponders, sidebars, bittings — and most people only run into these words in a stressful moment, standing at a locked door or reading an invoice they don’t fully understand.
Below you’ll find 160+ terms, organized A to Z, plus quick-reference tables for lock grades, key types, car key styles, cylinder formats, and the tools of the trade. Use the jump links to skip to any letter. This is a living reference from the team at Defense Locksmith, Buffalo’s mobile locksmith — we update it as the trade evolves.
“Half of doing this job well is translating. A customer doesn’t need to know what a shear line is to get their door open, but when they understand why a rekey beats a replacement, or why a dealer wants $400 for a key we cut for a fraction of that, they make better decisions. That’s what this dictionary is for.” — Simon Goodman, owner, Defense Locksmith
Jump to a Letter
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
Quick-Reference Tables
Table 1: ANSI/BHMA Lock Grades at a Glance
| Grade | Best for | Cycle test | What it means in real life |
|---|---|---|---|
| Grade 1 | Commercial, high-traffic, entry doors | 800,000+ cycles | The strongest residential/commercial standard — heavy-duty, drill- and wrench-resistant. |
| Grade 2 | Light commercial, quality residential | 400,000 cycles | A strong everyday choice; more than enough for most homes. |
| Grade 3 | Basic residential, interior doors | 200,000 cycles | Entry-level security; fine for closets, adequate as a bare minimum on exterior doors. |
Table 2: Car Key Types & What Replacement Involves
| Key type | Era | How it’s replaced | Programming needed? |
|---|---|---|---|
| Mechanical (metal) key | Pre-1995 mostly | Cut by code or to the lock | No |
| Transponder key | ~1996–present | Cut + chip programmed to the car | Yes |
| Remote head key | 2000s–present | Cut + transponder + remote programmed | Yes |
| Flip key | 2000s–present | Cut blade + program chip/remote | Yes |
| Smart / proximity key | 2010s–present | Programmed to the vehicle; emergency blade cut | Yes |
Table 3: Lock Cylinder Formats
| Format | Where you’ll see it | Notes |
|---|---|---|
| Key-in-knob (KIK) | Residential knobs/levers | Cylinder lives inside the knob. |
| Rim cylinder | Rim locks, some deadbolts | Mounts through the door, held by a backplate. |
| Mortise cylinder | Commercial mortise locks | Threaded body screws into the lock case. |
| Euro profile cylinder | European doors, some patio doors | The classic “double-D” shape; easy swap. |
| Interchangeable core (IC) | Master-keyed commercial systems | Pull and swap with a control key — no disassembly. |
A
All Keys Lost (AKL). The situation where no working key exists for a vehicle or lock. For cars, this is the hardest and most expensive key job because the locksmith can’t clone an existing key — they must generate a brand-new key from the vehicle’s data and program it to the immobilizer, sometimes reading the code from the lock or the car’s computer. See also Transponder, Immobilizer. Related service: lost car keys.
ANSI/BHMA Grade. The American National Standards Institute and Builders Hardware Manufacturers Association rate locks Grade 1, 2, or 3 for durability and security (see Table 1). When someone says a deadbolt is “Grade 1,” they mean it survived 800,000+ test cycles and resisted defined force and drill attacks.
Astragal. A molding or strip attached to the edge of one door in a pair of double doors, closing the gap between them. On secured double doors, an astragal covers the seam so the latch or bolt can’t be reached from outside.
Auto Locksmith. A locksmith who specializes in vehicles — cutting and programming car keys, fixing ignitions, and handling lockouts. Modern auto work is as much computer programming as it is mechanical. See our automotive locksmith services.
B
Backset. The distance from the edge of the door to the center of the bore hole (where the knob or deadbolt sits). In North America it’s almost always 2⅜” or 2¾”. Order the wrong backset and the lock won’t line up with the hole in your door.
Bible. The upper part of a pin-tumbler lock cylinder housing that holds the top (driver) pins and springs. Nothing religious — just the trade name for that chamber block.
Bitting. The pattern of cuts on a key — their depths and spacing. The bitting is what makes your key unique; it’s usually expressed as a series of numbers (a “bitting code”) that tells a locksmith exactly how to cut a duplicate. See also Key Code.
Bump Key. A specially cut key used in a technique to open pin-tumbler locks. We mention it here only for definition completeness — the real takeaway for homeowners is that bump-resistant and high-security locks exist precisely to defeat this, and upgrading to them is the sensible response. See High-Security Lock.
Blank (Key Blank). An uncut key of the correct shape (keyway) for a given lock, ready to be cut to a bitting. Every lock brand and keyway has its own blanks; matching the right blank is step one of cutting any key.
Bolt. The metal bar that extends from a lock into the door frame to secure it. A deadbolt is thrown by turning a key or thumbturn; a latch bolt is spring-loaded and retracts when you turn the handle.
Bored Cylindrical Lock. The most common residential lockset, installed in two round bored holes (one through the face, one in the edge). Knobs and levers you see on most homes are bored cylindrical locks.
C
Cam. The flat metal tab on the back of a cylinder that rotates when the correct key turns, actuating the bolt or latch. When the key turns but “nothing happens,” a broken or slipping cam is a common culprit.
Change Key. In a master key system, the individual key that opens only one lock (as opposed to the master key that opens many). Each tenant or room gets a change key. See Master Key System and our master key systems for landlords.
Combinating (Combination). The process of choosing and setting the pin lengths in a cylinder so a specific key operates it. “Combinating a lock” is trade-speak for pinning it to a key. Not to be confused with a combination padlock’s number code.
Core. The plug-and-housing assembly that holds the pins. In interchangeable-core systems, the entire core can be removed and swapped with a control key — the fast way to rekey many doors.
Cylinder. The part of the lock you put the key into — it contains the pins and the plug that turns. Cylinders come in several formats (see Table 3).
Cross Keying. Deliberately pinning a cylinder so that more than one otherwise-unrelated key will operate it. Used in master systems for special access needs — but it reduces security and is used sparingly.
D
Deadbolt. A lock with a solid bolt that can only be moved by turning the cylinder — it has no spring, so it can’t be “loided” (slipped with a card). The single most cost-effective security upgrade for most homes. Single-cylinder deadbolts use a key outside and a thumbturn inside; double-cylinder deadbolts need a key on both sides.
Deadlatch (Deadlocking Latch). A spring latch with a small secondary plunger that, when the door is closed, prevents the main latch from being pushed back — defeating the credit-card trick. Common on storefront and glass doors.
Detainer. Any component inside a lock that must be moved to the correct position for the lock to open — pins, discs, levers, and wafers are all types of detainers.
Disc Detainer Lock. A lock that uses rotating discs instead of pins, aligned by a specially shaped key. Common in high-security padlocks and some bike locks; harder to manipulate than standard pin tumblers.
Dimple Key. A key with cuts (dimples) drilled into the flat faces of the blade rather than the edge. Dimple keys drive pins from the side and are typically found on higher-security cylinders.
Double-Cylinder Lock. A deadbolt requiring a key on both the inside and outside. It stops an intruder who broke a nearby window from simply reaching in and turning a thumbturn — but it can be a fire-safety hazard, so use with care on exit doors.
Driver Pin. The upper pin in a pin-tumbler stack, pushed down by a spring. When the right key raises the key pins to the shear line, the driver pins clear the plug and it can turn. See Shear Line.
E
Egress. The act or means of exiting a building. “Free egress” is a code requirement that people can always get out without a key or special knowledge — the reason panic bars and certain lock functions exist. See Panic Bar.
Electric Strike. A door-frame device that replaces the fixed strike plate and releases the latch electrically — the “buzz-in” you hear at an office or apartment entry. Can be wired fail-secure or fail-safe. See our access control services.
Escutcheon. The decorative and protective plate around a keyhole, knob, or handle. Beyond looks, a solid escutcheon can shield the cylinder from attack.
EIS / ELV / Immobilizer Box. The electronic ignition/immobilizer module in modern cars (Mercedes calls it EIS/ELV) that verifies the key’s chip before allowing start. Faults here can mimic a “bad key” — diagnosis matters. See Immobilizer.
F
Fail-Safe vs. Fail-Secure. How an electrified lock behaves when power is lost. Fail-safe unlocks on power loss (used where people must exit, e.g., stairwell doors). Fail-secure stays locked on power loss (used to keep areas secure). Choosing correctly is both a security and a life-safety decision.
Fence. In a lever lock, a fixed pin that drops into the gate of the levers only when they’re all lifted to the right height — then the bolt can move. The lever-lock equivalent of a shear line.
Fire-Rated Door/Hardware. Doors and locks tested to hold back fire for a rated period (20, 45, 60, 90 minutes). Fire-rated openings require self-closing, positive-latching hardware and cannot be propped or modified in ways that break the rating.
Flip Key. A car key whose metal blade folds into the fob body at the press of a button, like a switchblade. Combines a remote, transponder, and blade in one unit. See our car key replacement.
Follower. A cylindrical tool a locksmith uses to push a lock plug out of its housing while keeping the top pins and springs from spilling — essential for rekeying without a mess.
G
Gate. A notch cut into a lever (in lever locks) or a slot in a sidebar system that a fence or sidebar must enter for the lock to open. Aligning the gates is the whole game in those lock types.
Grand Master Key (GMK). In a multi-level master system, a key that opens everything across several master-keyed groups. Above it can sit a Great Grand Master. Below it are individual master keys and change keys. See Master Key System.
Grade (Lock Grade). See ANSI/BHMA Grade and Table 1.
H
Handing. Which way a door swings and which side the hinges are on — left-hand, right-hand, left-hand reverse, right-hand reverse. Order a handed lockset wrong and it won’t function correctly. To find handing, stand outside facing the door: hinges on the left = left-hand.
High-Security Lock. A lock built to resist picking, bumping, drilling, and unauthorized key duplication, usually carrying a UL 437 or ANSI 156.30 rating and restricted keyways. Brands like Medeco, Mul-T-Lock, and ASSA are common examples. The right call for high-value doors.
Hinge. The hardware that lets a door pivot. Security-wise, exterior door hinges should have non-removable or set-screw pins so the door can’t be lifted off from outside.
Hook (Hook Bolt). A hook-shaped bolt used on sliding doors and some cabinets; it hooks into the frame so the door can’t be lifted or slid open.
I
Immobilizer. A vehicle anti-theft system that prevents the engine from starting unless it detects the correct transponder chip in the key. Introduced widely in the late 1990s, it’s the reason you can’t just cut a car key at the hardware store anymore — the key must be programmed to the immobilizer. See Transponder, All Keys Lost.
Impressioning. A skilled technique for making a working key for a lock without disassembling it, by reading marks left on a blank as it’s manipulated in the keyway. A craft skill, largely replaced by decoding tools but still taught.
Interchangeable Core (IC). A lock core designed to be removed and replaced quickly with a special control key — no tools, no disassembly. The backbone of large master-key systems where locks must be rekeyed fast. Comes in SFIC (small format) and LFIC (large format).
Ignition Cylinder. The lock the car key turns to start the engine (in non-push-button cars). Worn ignitions cause keys to stick or refuse to turn; we repair and replace them — see ignition repair.
J
Jamb. The vertical sides of a door frame. The strike plate and bolt engage the jamb, so a reinforced jamb (or a longer strike screw into the stud) dramatically improves kick-in resistance.
Jiggler Key. A set of roughly cut keys sometimes used to open low-quality wafer locks by wiggling. Their existence is a reason to avoid cheap wafer locks on anything you value.
K
Keyway. The shaped slot a key slides into, and the profile that determines which blanks fit. A restricted keyway limits who can buy blanks — a key-control feature. See Restricted Keyway.
Key Code. The number that represents a key’s bitting. A direct code literally states the cut depths; a blind code must be cross-referenced in a manufacturer chart. With a code, a locksmith can cut a key without the original — a huge convenience and a security consideration.
Keyed Alike (KA). Multiple locks set so one key operates all of them — convenient for a home where the front, back, and garage doors share a key.
Keyed Different (KD). Locks that each require their own separate key. The opposite of keyed alike.
Key Pin (Bottom Pin). The lower pin in a tumbler stack that the key actually touches. Its length is matched to the cut depth so the top of the key pin reaches exactly the shear line.
Key Blank. See Blank.
Kwikset / KW1. A ubiquitous residential lock brand; “KW1” is its most common keyway/blank. Locksmiths reference keyways like KW1 (Kwikset) and SC1 (Schlage) constantly because they dictate which blank and cutter to use.
L
Latch. The spring-loaded, beveled bolt that clicks a door shut when you pull it closed, retracting when you turn the handle. A latch alone is not security — that’s what deadbolts are for.
Lever Lock. A lock that uses stacked levers (instead of pins) that must each be lifted to the right height for the fence to pass and the bolt to move. Common in safes, cabinets, and older/European doors.
Lever Handle. A door handle you push down rather than grip and turn — easier for kids, the elderly, and ADA compliance. The mechanism inside can be the same as a knob lock.
LSDA / Lockset. “Lockset” refers to the complete assembly — handle, latch, cylinder, and trim — sold and installed as a unit.
Loiding. Slipping a spring latch with a thin card or shim (the “credit card trick”). Defeated by a deadlatch or a deadbolt. See Deadlatch.
M
MACS (Maximum Adjacent Cut Specification). The biggest allowable difference in depth between two neighboring cuts on a key. Exceed the MACS and the key can’t be cut cleanly or won’t work. It’s a key constraint when designing master systems.
Master Key System. A keying hierarchy where individual change keys open single doors, a master key opens a group, and higher-level keys open more — up to a grand master. Ideal for apartments, offices, and multi-unit buildings. Design it right (MACS, keyspace, interchange) or keys start opening the wrong doors. Try our free master key system designer.
“A master key system is a promise: this key opens exactly these doors and no others. Break the math — too many master pins, cuts too close together — and you’ve quietly handed people access you never intended. Half of what we fix in commercial buildings is a master system somebody set up on a spreadsheet without the geometry.” — Simon Goodman, Defense Locksmith
Master Pin (Master Wafer). A small extra pin placed in a chamber so a cylinder responds to more than one key height — the mechanical trick that makes master keying possible. Each master pin adds a “shear point,” which is why over-mastered locks lose security.
Mortise Lock. A rectangular lock body installed into a pocket (“mortise”) cut into the edge of the door. Heavy-duty and long-lived, standard on commercial and older quality doors. See mortise lock repair.
Mul-T-Lock. A well-known high-security brand using a telescoping pin-in-pin design and patented, restricted keys. A common recommendation when key control matters.
N
Night Latch. A rim-mounted spring latch (often with a deadlocking function) fitted to the surface of a door, historically used as a secondary “night-time” lock. Still common on apartment and shop doors.
Non-Destructive Entry. Opening a lock without damaging it — picking, decoding, bypassing, or using tools — so no hardware needs replacing afterward. Always our first approach on a lockout when time and the lock allow.
O
OEM Key. An “original equipment manufacturer” key — made to the vehicle or lock maker’s exact spec. For cars, OEM keys can be pricier than quality aftermarket equivalents that perform identically once programmed.
On-Site Programming. Cutting and programming a car key at your location using diagnostic tools that talk to the vehicle’s computer — no tow to the dealer. The core of modern mobile auto locksmithing.
Overlift. Turning a key or pick so a pin is pushed above the shear line, jamming the lock. Understanding overlift is part of why a worn or wrong key sometimes “sticks.”
P
Panic Bar (Exit Device / Crash Bar). The horizontal bar on commercial exit doors that unlatches the door when pushed, guaranteeing free egress in an emergency while staying secured from outside. Required on many occupancies by fire code. See panic bar installation.
Pin Tumbler. The world’s most common lock mechanism: stacks of spring-loaded pins that the correct key raises so their gaps line up at the shear line, freeing the plug to turn. Invented in its modern form by Linus Yale Jr. in the 1860s.
Plug. The rotating inner part of a cylinder that you insert the key into. When the pins clear the shear line, the plug turns and drives the cam. See Cam, Shear Line.
Profile Cylinder. See Euro Profile Cylinder in Table 3 — the “double-D” cylinder common in Europe and on many patio and storefront doors.
Proximity Key (Prox / Smart Key). A car key that stays in your pocket; the car detects it and lets you start with a button. Also, in access control, a prox card/fob read by holding it near a reader. See push-to-start programming.
Pin Stack. The full column in one chamber: key pin + any master pins + driver pin + spring. A standard cylinder has five or six pin stacks.
Q
Quick-Set / Rekeyable Cylinder. A consumer lock design (e.g., Kwikset SmartKey) that lets the owner reset the lock to a new key with a special tool, without disassembly. Convenient, though generally lower on the security scale than a locksmith-grade rekey.
R
Rekey. Changing the pins inside an existing lock so a different key works and all old keys stop working — without replacing the hardware. Faster and cheaper than replacement, and the right move after a move-in, a lost key, a break-up, or a tenant turnover. See lock rekeying.
Restricted Keyway. A patented key profile whose blanks are controlled — only authorized dealers can cut them, and only with proof of authorization. This is how you stop a former employee or tenant from quietly copying a key. Central to real key control.
Rim Cylinder. A cylinder that mounts through the door and is held by a backplate on the inside, driving a rim lock or night latch. See Table 3.
Rim Lock. A lock mounted on the surface (rim) of the door rather than inside it — common as a secondary lock and on older doors.
Rotating Constant. In master-key math, a cut position kept constant across a group of keys to expand the usable keyspace while preventing interchange. The kind of detail our designer tool handles automatically.
S
Schlage / SC1. A major residential/commercial lock brand; “SC1” is its most common keyway. Along with Kwikset’s KW1, one of the two keyways a home locksmith cuts most.
Shear Line. The precise gap between the plug and the housing where, when every pin stack is raised to exactly the right height, the plug is free to rotate. Getting all pins to the shear line at once is what “unlocking” mechanically means. See Pin Tumbler.
Shim. A thin strip of metal used to bypass certain latches or padlocks, or (in the trade) to hold pins while rekeying. Also the verb for that action.
Sidebar. A secondary locking bar (found in high-security and automotive locks like GM’s) that must be released by side cuts or dimples on the key in addition to the main pins — a big jump in pick resistance. See VATS.
Single-Cylinder Deadbolt. A deadbolt with a keyed cylinder outside and a thumbturn inside — the standard, code-friendly choice for most residential exterior doors.
Smart Lock. An electronic lock you operate with a code, phone app, fingerprint, or fob — often with remote access and logs. Great for rentals and no-more-hidden-keys living. See smart lock installation.
Spool Pin (Security Pin). A driver pin shaped like a spool (or mushroom, or serrated) that catches at the shear line to resist picking — giving false feedback to anyone manipulating the lock. A hallmark of better cylinders.
Strike Plate. The metal plate on the door jamb that the bolt or latch enters. Upgrading to a heavy strike with 3″ screws driven into the framing stud is one of the cheapest, most effective anti-kick-in upgrades there is.
Storeroom Function. A lockset function where the outside lever is always locked (key required to enter) but the inside lever always allows free exit — common on commercial storerooms and back doors.
T
Thumbturn. The small lever on the inside of a deadbolt you twist to throw the bolt without a key. Convenient and code-friendly for egress; the trade-off addressed by double-cylinder locks near glass.
Tension Wrench (Turning Tool). The tool that applies light rotational pressure to a plug during picking or decoding. Half of manipulation is tension control — too much or too little and nothing sets.
Transponder. The tiny radio-frequency chip embedded in a modern car key’s head that sends a coded signal to the car’s immobilizer. No valid chip, no start — even if the metal blade turns. Replacing a transponder key means cutting the blade and programming the chip. See transponder key programming.
Tubular Lock. A lock with pins arranged in a circle and a round key (think older vending machines and bike locks). Recognizable by its cylindrical keyway.
Tumbler. A general term for the moving detainers inside a lock — pins, wafers, discs, or levers — that a key must align.
U
UL 437. An Underwriters Laboratories standard for high-security locks, testing resistance to picking, drilling, and forced entry for a defined time. A UL 437 stamp is a genuine mark of a serious lock.
Unrestricted Keyway. A standard keyway whose blanks anyone can buy and cut — convenient, cheap, and copyable by anyone. Fine for low-stakes doors; a liability where key control matters.
V
VATS (Vehicle Anti-Theft System). An early GM anti-theft setup using a resistor pellet in the key that the car reads — a precursor to modern transponders. Copying a VATS key requires matching the exact resistance value.
VVDI / Autopropad / Diagnostic Programmer. Handheld tools locksmiths use to read a car’s immobilizer data and program new keys on-site. The modern auto locksmith’s most important instrument.
VIN (Vehicle Identification Number). The unique 17-character ID of a vehicle. With proof of ownership, a locksmith can sometimes pull key codes from the VIN to originate a key. Try our find car by VIN tool.
W
Wafer Lock. A lock using flat wafers instead of pins — cheaper and common in cabinets, cars (older), and low-security applications. Faster to pick than a good pin tumbler.
Ward. An obstruction inside a keyway (or old warded lock) that blocks any key of the wrong shape from entering or turning. The oldest locking principle still in use, mostly decoratively today.
Warded Lock. An ancient, simple lock relying only on wards to block wrong keys — the “skeleton key” locks of old homes and furniture. Low security by modern standards.
X · Y · Z
Yale. Both a founding name of the modern pin-tumbler lock (Linus Yale Jr.) and a major lock brand still in use worldwide. When someone calls a cylinder lock a “Yale,” they usually mean a rim night-latch style.
Zero-Bitted Cylinder. A cylinder pinned to the shallowest possible cuts, used as a starting point when a locksmith is about to combinate it to a new key. A blank slate, mechanically speaking.
Table 4: Common Keyways You’ll Hear Us Mention
| Keyway code | Brand | Typical use |
|---|---|---|
| KW1 | Kwikset | Most common residential |
| SC1 | Schlage | Residential & light commercial |
| SC4 | Schlage | 6-pin Schlage |
| WR5 / WR3 | Weiser | Residential |
| Y1 / Y11 | Yale | Rim & mortise |
Table 5: Tools of the Trade
| Tool | What it does |
|---|---|
| Pick & tension wrench | Non-destructive opening of pin-tumbler locks |
| Plug follower | Holds top pins while the plug is removed for rekeying |
| Key machine (duplicator/code cutter) | Cuts keys by copy or by code |
| Pinning kit | Assorted pins/springs for rekeying and master keying |
| Diagnostic programmer (VVDI, AutoProPad) | Reads immobilizer data, programs car keys on-site |
| Lishi decoder | Picks and decodes a lock’s cuts simultaneously |
Table 6: “Which Service Do I Need?” — Quick Match
| Your situation | The term for it | What we do |
|---|---|---|
| Moved into a new home | Rekey | Rekey every exterior lock so old keys die |
| Lost the only car key | All Keys Lost | Originate + program a new key on-site |
| Key turns but car won’t start | Immobilizer / transponder fault | Diagnose chip vs. module; reprogram or repair |
| Locked out of the house | Lockout / non-destructive entry | Open without damage where possible |
| Managing a rental building | Master key system | Design and install a keying hierarchy |
| Old key sticks in the ignition | Worn ignition cylinder | Repair or replace the cylinder |
“People are surprised how much of this is mechanical common sense once the words are demystified. A lock is just a puzzle that only your key solves. Our job is to solve it faster than the puzzle was designed for — and to build you a better puzzle when you need one.” — Simon Goodman, Defense Locksmith
12 More Terms Worth Knowing
Padlock. A portable, detachable lock with a shackle (the U-shaped loop) that secures gates, sheds, lockers, and chains. Quality varies enormously — look for a hardened boron shackle and a shrouded body on anything you actually care about.
Shackle. The curved bar of a padlock that passes through whatever you’re securing. A “shrouded” or “closed” shackle hides most of it from bolt cutters.
Cam Lock. A simple cylinder lock with a flat metal cam that rotates to secure cabinets, mailboxes, and drawers. The little locks on a cluster mailbox are cam locks.
Bolt Throw. How far the bolt extends out of the lock when engaged. A full 1-inch throw on a deadbolt buries the bolt deep in the strike — much harder to force than a short throw.
Latch Guard. A metal plate installed over the gap between an out-swinging door and its frame, blocking tools from reaching the latch. A cheap, effective commercial-door upgrade.
Door Reinforcement Kit. Hardware (wraparound plates, longer screws, strike-box reinforcements) that hardens a residential door against kick-ins — often more valuable than a fancier lock.
Snap Gun (Pick Gun). A tool that snaps all pins upward at once to momentarily clear the shear line. Mentioned for completeness; good spool pins and tight tolerances resist it.
Keyed Cylinder. Any cylinder operated by a key (as opposed to a thumbturn or electronic input). The generic term for “the part the key goes in.”
Blind Code vs. Direct Code. A direct code states the actual cut depths; a blind code is a lookup number that must be cross-referenced in a manufacturer chart to reveal the cuts. Blind codes add a layer of security.
Interchange (Key Interchange). When a key accidentally opens a lock it shouldn’t — the nightmare of a badly designed master system. Proper keyspace math (MACS, rotating constants) prevents it.
Escutcheon Plate. See Escutcheon — the trim plate around a lock or handle that both finishes the look and can protect the cylinder.
Dead Latch Plunger. The small secondary pin beside a spring latch that, when depressed by the closed door, locks the main latch against being slipped. The mechanical reason a proper storefront latch resists the card trick.
Frequently Asked Questions
Is rekeying as secure as replacing a lock?
Yes — if the existing lock is in good shape. Rekeying changes the pins so every old key stops working, which is exactly what you want after a move or lost key. You only need replacement when the hardware itself is damaged, worn, or too low-grade to trust.
Why can’t I just copy my car key at a hardware store?
Because a modern car key has a transponder chip that must be programmed to your specific vehicle’s immobilizer. A hardware store can cut the metal blade, but without programming the chip, the car won’t start. That’s a job for an auto locksmith with a diagnostic programmer.
What’s the difference between a latch and a deadbolt?
A latch is the spring-loaded bolt that clicks your door shut and retracts when you turn the handle — convenient, but easy to slip. A deadbolt has a solid bolt with no spring that only moves when you turn the key or thumbturn, making it far more secure. Every exterior door should have a deadbolt.
What does “Grade 1” mean on a lock?
It’s the ANSI/BHMA rating for the highest durability and security tier — the lock survived 800,000+ operating cycles and defined drill/force tests. Grade 2 is a strong residential choice; Grade 3 is entry-level.
Can you make a key with no working key at all?
Usually yes. For homes, we can decode the lock or pull a code; for cars, we originate a new key from the vehicle’s immobilizer data and program it — the “all keys lost” service. Bring proof of ownership.
Have a Term We Missed? Or Need the Real Thing?
This dictionary is maintained by the team at Defense Locksmith — Buffalo’s fully mobile lock, key, and security experts. If a word left you more confused than before, or you’re standing at a door that won’t open, skip the glossary and call a human: (716) 803-2934. We handle residential, commercial, automotive, and safe work across the Buffalo metro, 24/7. Bookmark this page — we keep adding terms.