A selection of common terms in architectural hardware



Active Door: [In a pair of doors] The leaf that opens first and has the lock/latch.

Armored front, or Scalp: A lock front for mortise locks consisting of a heavier inner faceplate which is permanently riveted or is screwed to the lock case. It is covered by a finish outer plate machine screwed to the inner faceplate. For cylinder locks, it consists either of two separate plates with the inner one made a permanent part of the lock body and a finish plate secured with wood or machine screws. The two plate may also be permanently joined by hollow rivets that allow mounting by finish screws.

Astragal: A molding applied to the meeting edge of a pair of doors to protect against weather.

Backplate: An escutcheon larger than a rosette, used as a means of mounting a handle.

Backset: The distance from the edge of the door to the center of the hole drilled for the knob, lever, thumbturn or keyed cylinder. A 2-3/8" or 2" backset is standard for residential doors. Backsets of 1" to 5", even 24" are available.

Bar Latch: Simple latch mechanism mounted on the surface of a gate, cabinet door, shutter, or small closet door. Operated by raising a hinged lever attached to the door. Usually includes a flat strike plate, lever, and guide.

Bore: Bore is the diameter of the hole drilled in the face of a door stile to receive the spindle for the handles; for the body of particular cylindrical latch mechanisms or for the body of a keyed cylinder, deadbolt or thumbturn.

Cam: A piece of metal applied to the back of the cylinder plug to activate the lock. Mortise locks require specific cams to operate.

Cane Bolt: A type of door anchor that pushes a long metal bolt through two surface-applied brackets and into a socket. Usually used to keep gates in the closed position.

Carriage Bolt: A bolt with a smooth, round head used in wood. Since the head is rounded, a small square section under the head keeps the bolt from spinning while the nut is tightened on the other side.

Casement Stay or Adjustor: A pivoting rod for moving and securing the hinged sash of a casement or French window. It is mounted to the sash bottom rail and window sill for out-swinging sash, or to the interior casing for in-swinging sash.

Casement Fastener: The handle that open and secures a casement window. Typical design is of a handle with projecting tongue that engages the strike.

Casement Window: A type of window that opens like a door on butt hinges, or on scissor hinges that allow the window to pivot within the opening. Typical mechanisms to open and close the window are either a manual crank, a casement fastener or a handle for a multipoint lock. European style casement windows may also have a Tilt & Turn function, which requires a lever-operated mechanism. The handle swings up to open the window a few inches at the top of the frame; or it will swing down to open the window like a traditional casement window.

Casement Fastener Strikes: 
Mortise Strike - a flat strike that is set flush in the face of the jamb or stop.
Surface Strike - a strike has a wedge-shaped face that secures the tongue of the casement fastener. It is mounted on the face of the inactive leaf of a double casement window with the fastener mounted on the active leaf. The inactive leaf should be secured with an edge or surface bolt at top and/or at bottom.
Rim Strike- A flat strike with a hook for in-swinging single casement windows.

Center-to-Center: Measurement from the center of one item to the center of another. Used when determining spacing between latches and deadbolts, etc.

Change Key: A key which will operate only one lock in a series, as distinguished from a master key which will operate all locks in a series.

Clavos: Wrought-head nails used to decorate doors; it is the Spanish word for nails.

Cremone Bolt: A reciprocating surface-mounted decorative bolt mechanism most often used on French doors and windows. Traditionally, an oval knob or lever engages a gearbox that drives surface bolts upwards and downwards into strikes at both the top jamb of the opening and the sill, threshold or floor.

Closet Spindle: A spindle with a knob or lever on one end and a thumbturn on the other end; generally used for closet doors.

Crossbore: The hole that is drilled through the face of the door that receives the spindle or handle hub of a knob or lever . Door knobs and levers must fit the crossbore on pre-drilled doors and conceal the hole.

Cylinder Lock or Latch: Any lock or latch mechanism contained in a cylinder. Most commonly used on entry doors where a key cylinder allows lock operation on the exterior and thumbturn is used on the interior. A double cylinder is used in instances where key operation is needed on both sides.


Deadbolt: Deadbolts can be a single cylinder or double cylinder locking mechanism. Single cylinder deadbolts have exterior keyways and interior thumb turns, while a double cylinder deadbolt requires a key on both sides and is subject to egress building code.

Deadlatch: It is a latch which secures the door closed, but can be withdrawn by key from outside and by knob or handle from inside.

Deadlock: A standard deadbolt lock that is operated by key, thumbturn, or combination of both.

Door Thickness: The thickness of a door where hardware is to be installed. Most common door thicknesses are 1-3/8" for interior doors, and 1-3/4" for entrance doors. About 10% of entrance doors are 2-1/4" thick.

Door Stop: It is the strip of molding roughly 1" in width that prevents the door from opening the wrong way. The door-stop lines the jamb and also hides the gap between the door and the jamb.

Doorstops: A device used to limit the opening swing of the door. They are typically mounted on the baseboard or floor.

Double-acting: A door that swings both ways.

Double Cylinder: Two-sided key cylinder that allows key operation on both sides of the door. Useful for instances where the door is situated next to a window, as it prevents a burglar from reaching in and opening a deadbolt thumbturn. (See Single Cylinder.)

Dummy: Non-functional door hardware. In door pairs, the inactive door will often have a dummy lever or knob set. (See Inactive Door.)

Dummy Spindle: A short-threaded square steel rod attached to a metal base that allows knob to be mounted to door with no internal latch mechanism.

Dummy Strap: Decorative door hardware that accompanies a normal butt hinge, giving the butt hinge the appearance of an actual strap hinge. (See Strap Hinge.)

Dustbox: In a door lock assembly, the dustbox is a plastic or metal box that sits behind the strike and encases the bolt, protecting it from dust and debris.

Edgebore: Hole drilled into the edge of the door, through which the bolt extends once assembly is installed.

Edge Pull: A recessed pull mortised into the edge of a pocket door.

Emergency Exit Lockset: Lockset where interior knob or lever retracts both latch and deadbolt at the same time, allowing for quick exit.

Emergency Release: A small hole on the outside of a privacy door that allows access in case of an emergency.

Escutcheon: Any trim used behind a knob or lever, or trim for keyholes and such.

Face Plate: The protective covering of the latch or lock system, located in the door.

Finials: Decorative tips found on hinges and other hardware. Only some hinges will accept these finials.

Flush Bolt: A bolt mortised into a door that holds the door closed when the bolt is projected, usually into the head or sill of the doorframe. In contrast with a surface bolt, the flush bolt is mounted flush with either the edge or face of the door. Flush bolts are often used to hold the inactive door in a pair closed, while the active door is kept open for regular use.

Flush Ring: A flush circular door pull that is mortised in door and is either fixed or turns as a latch handle.

Grille: A protective screen of open metal work, either wrought or cast; sometimes highly ornamental.

Gudgeon: A circular fitting which receives a pin, or pintle, allowing the pin to pivot in place. Commonly used in wrought lift-off type hinges.


Handing: is the way a door swings. Determines how latches and bolts need to be installed for proper operation. This is needed for certain lever sets, entrance sets, and mortise locks. When viewing the door from outside*, the handing is determined by which side the door hinges are hung. For instructions on how to determine the handing of your door, view our Handing Chart.
*Outside is defined as outside the house or outside the room the doorway leads to.

Hinge: There are a variety of hinges available for almost any situation. Here are some examples:
Butt Hinge: Hinge in which both leaves are mortised (cut) into the edge of door and frame. When the door is closed, the two halves are folded tightly.
Olive Knuckle: A hinge with an oval shaped single knuckle.
Offset Hinge: Used for cabinets or other furniture pieces where the door projects out from the frame, requiring an offset to accommodate the space between the surface of the cabinet frame and the door.
Floating-Pin Hinge: Hinge in which pin has no tip and is suspended in hinge knuckle between two threaded tips; must be unscrewed to remove the pin.
Half-Mortise Hinge: A hinge with one leaf that mounts on the surface of door, and one leaf that is mortised (cut) into the edge of the door frame. Commonly used where full surface hinges won't fit side-by-side on a narrow frame, or to lessen the amount of hardware showing.
Parliament Hinge: This is an "H" shaped hinge that is wider than it is tall to allow for a door or window to swing clear of the trim and lay flat when opened. Spring hinge: Either a surface mounted or full mortise hinge with spring tension to make the door swing shut.
Surface Hinge: Also known as flush or full surface, it is a which is mounted to the face of the door and door frame so that the entire hinge is visible when the door is closed.

Hub: The portion of a lock, tubular latch or mortise bolt which a knob/lever spindle or turnpiece spindle passes through to actuate the latch or bolt mechanism. Knob/ lever hubs are round with a square hole in the middle that is either set on the square or diamond. Typical hub size for knob/ lever is either 7.3 mm on the diamond or 8 mm on the square. Turnpieces hubs are typically 5 mm and set on the diamond.

Inactive Door: The leaf in a pair of doors that is usually bolted closed and which the strike is attached. Jamb: The wood frame around the door in which the door is hinged to on one side and where the latch catches on a boring on the opposite side.

Keyed Alike: Locks are identically keyed (can be used by the same key).

Kick Plate: A metal plate, at least 8" high, used to protect the full width of the door bottom rail. Knuckle: The round joint of a hinge through which a pin is inserted.

Latch: The latch is a spring-loaded bolt that moves with the turn of a knob or lever. It slides into the strike plate attached to the door jamb or inactive door, and holds the door shut or opens it. Also called a cylinder latch or tubular latch.

Bar Latch: Simple latch mechanism mounted on the surface of a gate, cabinet door, shutter, or small closet door. Operated by raising a hinged lever attached to the door.

Mortise Tube Latch: A latch mechanism with a rectangular body that requires a rectangular hole in door edge for installation.

Letter Box: Framed mail slot, with or without cover.

Lock rail: Typically, the mid-section horizontal member of a frame and panel door. Literally, the rail where the lock goes.

LTC: Refers to the lip to center dimension often used to size strikes and is the distance from the edge of the lip to the center of the hole.

Mortise Bolt: A door bolt designed to be mortised into it door, instead of being applied to its Surface; generally used as an interior privacy device.

Mortise Lock: Lock assembly that fits into a precut slot (mortise) inside the edge of the door. Generally, a mortise lock houses both the latch and the deadbolt, making bore spacing particularly important. Mortise Cylinder: A threaded cylinder used specifically for the mortise lock assembly.

Night Latch: An auxiliary lock having a spring-latch bolt and functioning independently and providing additional security to the regular lock on the door.

Non-rising pin: Used as a security device with butt hinges. A set-screw or other pin is set into the hinge pin to keep it from rising. Designated as NRP.


Patio Deadbolt: A Deadbolt set that is operated by a thumbturn only; there is no key operation.

Passage Function: Passage knob or lever sets that do not include locks and are usually used on interior doors. (Compare with Privacy knob and lever sets.)

Pintle: A pin that seats in a gudgeon creating a pivot hinge.

Privacy Function: Privacy sets are used on interior doors where a lock system is needed. Commonly found on bathroom and bedroom doors, sets with privacy function typically lock on only one side and have an emergency release hole on the other.

Push Plate: A plate, decorative or plain, used to protect a door where it is pushed to open.

Rabetted Lock: A mortise lock, the front of which is formed with a right angle offset or rebate conforming to the corresponding rebate on the edge of the door.

Rail: Term used for the horizontal pieces that constitute the top and bottom edges of a door.

Rim Lock: A type of surface-mounted, box-shaped lock from America's colonial period. Lock mechanism is mounted on the interior side of the door, while the strike box is surface-mounted on the door frame. Requires a rim cylinder for the entry door.

Roller Catch or Bolt: A type of door fastener that pushes a spring-loaded roller (mounted into the door) into an indented, jamb-mounted strike plate. Roller and strike plate can also be switched, where the plate is on the door and roller on the jamb. Typically used on doors with dummy hardware where the desired function is to push or pull the door open.

Rose (Rosette): A small plate behind lever or knob that holds the lever or knob in place.

Sash Window: A sash window usually refers to a double-hung setup that slides up and down.

Sash Lift: A handle mounted to the bottom rail of a double-hung window as a lift for the bottom sash. Either a flush cup or hook type.

Sill: The horizontal, bottommost part of a door or window frame. In a door, the sill rests on the foundation and supports the frame structure. In a window, the sill usually has a ledge-like protrusion.

Single Cylinder: A single lock that has key operation on the outside [exterior] and a thumbturn on the inside.

Snib: a button or catch to secure a lock from the interior side against exterior access.

Spindle: The piece of hardware which attaches two knobs [or levers] through a door. Typical spindle sizes are either 7.3 mm or 8 mm. Threading type determines what kind of knob will fit onto the spindle. They are available in different lengths to accommodate different door thicknesses.

Stile: The vertical elements of a doorframe or window frame; normally where hinges are attached and lock bolt is received. The stile is measured from the edge of the door to the first panel or pane of glass. This is necessary in determining backset.

Strap Hinge: A hinge with one long strap that extends across the surface of the gate or door, and one short leaf that attaches to the jamb.

Strike: A plate or other opening that is part of the lock assembly. Its function is to receive the bolt when the assembly is locked. In a single-door setup, the strike is mortised into the doorjamb; in a double-door setup, the strike is mortised into the inactive door. Types of strikes include, T-strike, full lip strike or D-strike, ASA strikes. Thick doors may require an extended lip strike which is wider then the standard strikes.

Surface Bolt: a device mounted on the surface of the passive (fixed) side of pair to allow it to remain shut tight while active side is in use. In a double-door setup, the surface bolt is used to secure the inactive door by pinning it to the floor or door jamb head. Secured to the surface of the door and operated manually with a small knob.

Swage: The offset of a hinge leaf from the centerline or the tangent of the barrel to allow the leaves to close parallel to each other.

Swivel Spindle: Typically used on privacy and entrance doors that have an emergency egress. The spindle allows the knobs or levers to operate independently to one another; allowing turning on one side, while holding the other side stationary to enforce the privacy lock.

Threading: Determines what type of knob can fit onto the spindle. Check this when building your own entrance or interior set from old or replacement plates and knobs.

Thumb-piece: Mounted above the grip handle of an entry lockset; the thumb-piece engages the latch.

Thumb-turn: Also called a turnpiece, a thumbturn is a lock component turned with thumb and fingers, thereby projecting or retracting the accompanying dead bolt or latch bolt.