Glossary Terms - C


Cam (of a cylinder) – A lobe or lever shaped rotating piece, attached to the back of the cylinder plug that engages the locking or un-locking mechanism.


device used for storing an electrical charge.


Case (lockcase) – The housing of a lockset containing most of the working parts.

Cased Opening

A frame profile that has no integral stops.

Casement Hinge

A hinge used to hang a casement window. Term used to indicate a hinge made to open the window sash out far enough to allow for cleaning the outside of the glass from inside the room on an outward-swinging casement.


Indicates that the individual, so identified is a Certified Construction Products Representative and a member of the Construction Specifications Institute.


Indicates that the individual, so identified is a Certified Door Consultant and member of the Door and Hardware Institute.


Indicates that the individual so identified, is a Construction Documents Technologist and a member of the Construction Specifications Institute.

Center Panel

The panel between the hinge and lock stile of a stile and rail door.

Center Pivot

Door hanging hardware that has the pivot axis located on the centerline of the door thickness. Usually located approximately 2-3/4 inches (69.8mm) from the hinge jamb

Center Rail

Horizontal rail in a Stile and Rail type door, usually located at the lock height. It is used to separate the upper and lower glass or panel areas of the door.

Center-Hung Door

A door hung on center pivots.

Change Key

As key that operates a particular bitting change within a key system. The change key can only operate one cylinder or group of keyed alike cylinders. Change Keys are the lowest level in a master key system.


The different bittings or tumbler arrangements available in a series of cylinders.


The housing containing most of the working parts.

Checking Floor Hinge

A device mounted in the floor that uses both top and bottom pivots to hang the door with a controlled-speed closing mechanism.


The path through which electrical energy flows in a loop connecting all components.


A hardware device that uses spring compression power and adjustable controlled hydraulics to control a door leaf at the proper speed and opening force.

Closer Blocking

Additional reinforcing added to a flush type wood door to accommodate a surface type closer.

Closer Bracket

A hardware device required for certain applications where the closer body is mounted on the frame rather than the door.

Closer Reinforcing

Reinforcing in a hollow metal or aluminum frame head or inside a hollow metal or aluminum door to provide additional strength for attachment of a door closer. May be a sleeve or plate type in the frame but is preferred as a channel or box type in the door.

Closer Screw

A valve that adjusts the flow of hydraulic fluid within the closer body to control the closing of the door.

Closing Speed

The speed at which a door swings from the open position to within a few degrees of latching. See Latching Speed.


A group of numbers representing the bitting numbers of a key or the tumblers in the lock cylinder.

Composite Core Construction

A hollow metal door using a solid core material bonded to a metal facing. Examples include polystyrene, polyurethane and solid temperature rise cores.

Composite Keyway

A keyway which has been enlarged to accept more than one key section, often key sections of more than one manufacturer.

Concealed Key Control (CKC)

The marking of standard key symbols ona cylinder in a location which is not visible once the cylinder is installed.


Material with the ability to carry electric current. Example: an electric wire.

Construction Core

A Removable or Interchangeable core used during the construction phase of a project. It is replaced by the permanent core when construction personnel no longer needs access.

Construction Keying

Construction Master Key (CMK) – A key normally used by the builder’s personnel for a temporary period during construction. It operates all cylinders designated for its use. The key is permanently voided by the owner when he accepts the building or buildings from the contractor.

Construction Break-Out Key (CBOK) - A key used by the owner to make all Construction Master Keys permanently inoperative.

Construction Master Key System

A key system used to operate cylinders throughout a construction project. Once voided, the key will not operate that cylinder but the permanent keys will. The change of key operation is accomplished without the manual re-keying of the cylinder.

Contact Ratings

Load rating of a switch. Ratings are at a maximum voltage or current.


Electrically conductive points, or set of points, used to make or break an electric current.

Continuous Duty

Refers to a solenoid or other device that can operate continuously with no off period.

Continuous Output

The normal rating available from a power supply.

Control Key

A key that is used to remove and install a removable or interchangeable core.


A hardware device mounted on a double opening frame, which ensures the inactive leaf is allowed to closer before the active leaf. This is necessary when certain combinations of an overlapping astragal, automatic flush bolts and panic devices are used with closers on both door leaves.


A complete unit, often with a figure 8 shape, which usually consists of the plug, shell, tumblers, springs, plug retainer and spring cover(s). It is primarily used in removable and interchangeable core cylinders and locks.

Corner Bracket

A special purpose closer bracket that is attached to a frame jamb and head on the hinge side. The closer attaches to the bracket in some out-swinging door applications.

Corrosion Protection

Additional painted covering on all external partsto deter oxidation and corrosion.


Something that is used to validate a user’s identity to grant access to a physical space or network resources. It can be something the user has (i.e., card, fob, or phone); something the user knows (i.e., PIN codes or combinations); and/or something the user is (i.e., biometrics such as fingerprints).

Cross Keying

Keys a cylinder to two or more separate Change keys. This practice offers convenience but always reduces security due to the elimination of pins or addition of multiples of Shear Lines available in the cylinders pin chambers.

Controlled Cross Keying – When two or more Change Keys under the same Master Key are to operate one cylinder.

Uncontrolled Cross Keying – When two or more Change Keys under different Master Keys are to operate one cylinder.


Energy flowing through a circuit. Current is either alternative current (AC) or direct current (DC).

Curved Lip Strike

A strike with the lip curved to conform to the detail of the door frame.


A preparation on a door or frame for hardware and/or accessories.


Cylinder (of a lock) – The cylindrical-shaped assembly containing the tumbler mechanism, usually consisting of a cylinder shell, cylinder plug and combinating pins with other miscellaneous parts, which can be operated by the correct key(s).

Cylinder Cam

The metal plate attached or activated by the cylinder rotation which actuates the locking mechanism.

Cylinder Collar

A spacing or trim type ring or plate installed under the head of a cylinder.

Cylinder Lock

A lock in which the locking mechanism is controlled by a cylinder.

Cylinder Plug

The round part of a cylinder that contains the keyway. It is rotated within the cylinder shell and has the cam, tailpiece or other actuating device attached to its end.

Cylinder Set Screw

A setscrew that prevents an installed cylinder frombeing rotated or removed.


Cylindrical (locks/latches) – A term describing bored locks that have a cylindrical body or case that connects with separate latch bolt cases.

Cylindrical Lock Preparation

Also known as a government 161 or 160 preparation, or ANSI- A115.2 or A115.3 preparation. The preparation consists of a cylindrical hold through the door face and a cut out and a mortise and/or tap plate in the door edge to receive the latchbolt. The face may also require an additional set of varying holes through the door for Thru-Bolted trim used with many lever designs. Hollow metal doors must have internal reinforcing added during manufacture to support the lock prep.