Locksmith Terminology Buster

Technical Locks and Locksmith Terminology Buster

Whether you are locked out, require your locks to be changed or need another Locksmith service, when calling a local Locksmith you want to be sure that you understand the lock terminology used by the Engineer to avoid any miscommunication.

Generally, the majority of Locksmiths will ask you a few questions about the door and the lock itself whether it’s an emergency or non-emergency situation.

We have put together the following Locksmith terminology buster to ensure you fully understand the terms used by Locksmiths. So when you do require a Locksmith, whether they talk about door lock parts terminology or lock picking terminology, you can be confident that you understand exactly what is being done onsite.


Parts of a Lock

Cylinder Housing – The main body of the cylinder when all of the other components are removed.

Forend – The part of the lock or latch from which the bolts jut, and where the lock is fixed to the door.

Keyhole / Keyway – The hole in which a key is entered to operate a locking mechanism. It is often referred to as a keyway for a cylinder mechanism.

Lever – A flat movable component that is usually moved by the key to operate the lock.

Lever Handle – A part of the lock or latch to operate the spring bolt, often the alternative to a knob.

Lock – A device operated usually with a key which has one or more bolts to fasten and secure.

Lockable Bolt – A bolt that can be shot and locked into position using a removable key.

Locking Latch – A latch with a spring bolt which can be locked and secured by a key.

Lockset – A lock complete with all necessary components.

Mortice – A hole cut into the thickness of a door to receive a mortice lock or latch.

Pin Tumbler Mechanism – The mechanism that operates a cylinder or cylinder pin tumbler lock. It consists of a series of pins differing in length that when the corresponding key is inserted the pins line up to allow for the lock to be operated.

Plug – The housing for the pins of a pin tumbler cylinder.

Wards – Fixed obstacles inside a lock case to stop the use of the wrong key.

four keys on white background


Parts of a Key

Blank Key / Key Blank – A incomplete key which has been purposely shaped to enter the keyhole of certain type of lock or latch but cannot operate the lock.

Bow of a key – The part of the key that is held when using the key to operate the lock or latch.

Bit of a key / Key Bit – The part of the key which is specifically designed and shaped to operate the mechanism of a particular lock or latch.

Key – A small device used to operate a locking mechanism.

Mortice Key – A key that operates a lever lock.

Shank of a key – The part on the key that connects the Bow and the Bit.

Skeleton Key – A key designed to fit many different locks by having the interior of the bit hollowed.


Door Lock Terminology

Bolt / Deadbolt – A solid piece of metal that protrudes from the Forend of the lock into the ‘keep’ fitted on the frame.

British Standard / BS3621 – The BS3621 signifies that a lock has been tested by the British Standards Institute and has met all the relevant standards. It is widely recognised by the public and most UK insurers as a sign of quality.

Cylinder – The key operated part of most locking systems. Available in many formats, for example Euro profile, Rim type, Oval.

Double Locking – A function that offers an extra locking facility on top of the standard operation.

Furniture – Any hardware fitted to a door other than the lock itself. Handles, door knocker etc.

Hinge Bolts – Small round bolts that are drilled into the hinge side of a door. They keep the door in the frame when the door is closed. Designed to prevent a door being lifted from its hinges and removed unless open.

Hook Bolts – Similar in principle to dead bolts, although for added security hook bolts pivot out of the case and swing up or down into the frame.

Jamb – The vertical member of a door or window frame.

Latch – Usually found used in conjunction with several other locking points (such as deadbolts).

Master Key – A key that is designed to be able to open more than one lock.

Spindle – A square bar that runs between two handles, passing through the lock body itself to allow the latch to be retracted when a handle is operated.

Suite (Locks) – More than one lock manufactured in sequence or to a specific non-random pattern.

Thumb Turn – A euro profile cylinder in place of the internal Key way to allow easy or quick egress.


Wooden Doors

Back Plate – A plate that fits directly to the door to provide a solid fastening for the hardware to be fitted to.

Cam Lock – A cylinder type lock that operates a tail to engage with the locking mechanism. Commonly fitted to furniture or basic safes.

Combination / Digital Locks – A keyless lock that uses a chosen combination of numbers or letters to release the lock.

Escutcheon – The plate or guard normally fixed over the keyway of a lock to protect it from the elements and offer an aesthetically pleasing finish.

Face Plate – A plate fitted to the front profile of the lock to provide an aesthetically pleasing finish and information about the lock behind it.

Mortice Lock – A lock that is fitted within a pocket cut into the door. When the door is closed the only visible parts are the keyways from both sides of the door.

Night Latch – A lock operated by a rim style cylinder. The lock is fitted to the back of the door and is operable by use of a handle from the inside. Available in many different sizes and security ratings.

Rim Cylinder – A cylinder used to operate a Night latch.

Sash Lock – Most commonly a mortice style lock that also utilises a latch operated by a handle.

Spring bolt – A bolt which can be pushed back into the lock case manually and will return to the extended position without mechanical assistance.

Snib – The small button or sliding button fitted most commonly to Night latches to allow the latch to be held in position.

Striking Plate – A flat, shaped metal plate that is fixed to the door frame or jamb with multiple bolt holes for which the bolts shoot.


uPVC Doors

Anti-Snap Cylinder – A cylinder specifically designed to help prevent cylinder or lock snapping. The ABS High Security Euro Cylinder is the only security cylinder currently on the market which has a TS007 3 star rating, SS312 Sold Secure Diamond Accredited and Secured by Design Accreditation combined. Check out our guide on How to Change a uPVC Door Lock Cylinder here!

Lever Mechanism – A lock mechanism consisting of one or more levers. Check out our guide on Fixing a Broken uPVC Door Lock Mechanism here.

Anti Snap lock with keys and description


Additional Security

Anti-thrust bolt – A type of spring bolt, predominantly found on a Night Latch, that cannot be forcefully pushed back once it has been deployed. It can be withdrawn using a knob or key

Anti-thrust plate – An overlapping metal plate that is fitted to outward opening doors to restrict access to the locking bolts.

Burglar Bars – Steel bars cut to length and fitted to internally to window frames.

Birmingham Bar – A steel bar fitted onto the internal hinged side of the door frame.

Shackle – The metal ‘loop’ at the top of the Padlock that fits through the eye of a hasp.

Closed Shackle Padlock – A padlock which has been manufactured with the shackle (the locking ‘loop’) largely encased within the main body.

Deadlock – A lock that has a square-ended deadbolt that is operated from either one or both sides by a key or internally by a thumb turn.

Door viewer – A device that allows the person inside of a property to view the person on the outside of the property through the door.

Door Closer – A device that closes a door or gate automatically after opening.

Door Chains and Limiters – A small chain that is attached to the door frame which attaches to a track on the door to prevent any unwanted visitors from entering a house after the door has been opened.

Flush Bolt – A door bolt which is flush into the edge or on the face of the door.

Hasp and Staple – A security feature in two parts that secures a door or box. It is the components to which a padlock is attached.

Hasp – The hinged component that is fitted to a door or a box that closes over the staple.

Staple – A looped component in which a padlock it attached to restrict the movement of the hasp therefore securing a door or box.

Shoot Bolt – A bolt designed to bridge the gap between the door and the frame, widely used as extra security.

Sash Jammer – A small piece of metal with a pivoting arm that bridges the gap between the frame and sash of a door or window. This is fitted to help prevent doors/windows from being jimmied open.

Key Safe – A strong mechanical box usually with a digital pad that is fitted externally to a home which is used to secure keys for an external door.


Still wondering what extra security you need and what you should avoid doing? Check out our Ultimate Guide to Home Security to see what protection you can give to your home.


Keytek Locksmiths


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Keytek® Locksmiths provide a professional, National emergency Local Mobile Locksmiths service across the UK. Providing a 30 minute* emergency response no matter where you live. Keytek® is committed to providing a fast and efficient service with highly trained and reliable Engineers.

When using Keytek® local mobile Locksmiths as a customer or business you can expect to receive a 365-day service, 1 hour emergency response time*, friendly DBS checked Engineers, full parts guarantee and a highly trained team to handle your call.


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