Here are some handy definitions of terms you may encounter while buying or installing a Caldwell’s door.


In paired doors, the hinged door leaf which is primarily operable.

Affidavit Label

A label that is placed on a fire-rated door in that a manufacturer states that the door meets certain test criteria.

Air Infiltration

Air passing through a door unit when the door is under pressure, usually from wind.

Annealed Glass

Glass which has been heat strengthened or tempered.


A wood or aluminum ‘post’ attached on the latch-side edge of one of a set of paired or double doors, which covers the space between doors when they are closed. Which acts like a stop for the active door.


Recess- or spacing, for locating a machined hole. The distance from an edge or surface to the center or edge of the recess.

Ball Catch

A spring-loaded ball mechanism that is inserted into the top edge of doors that have dummy locks. The ball engages a plate on the header that has a dimple to receive the ball, which in turn keeps the door closed.

Ball-Bearing Hinge

A heavier-duty hinge than the standard hinge, with bearings supporting the pivots. Ball-bearing hinges are usually used for heavy doors that will be in commercial or industrial use.


A term used for the rubber part at the bottom or top end of an astragal, which beds the astragal end and seals between the end and the door frame or sill.

Boss, Screw Boss

A part that enables the fastening of a screw into the feature, thereby allowing assembly of the part with another. Screw bosses are common features of molded plastic lite frames and extruded aluminum doorsills.


In door and sidelite assemblies, a term used to differentiate door and sidelite units which are first framed as separate units. Box-framed doors are joined to box-framed sidelites.


A small nail with a small head, usually used to fasten small trim and moldings, also known as a finish nail.


A molding- type of door casing. Used to trim the outside edge of an exterior door frame.


A term usually used in masonry construction to describe a door frame or a sub-frame in a masonry opening, around which a steel door frame wraps and is fastened.


Butt hinges are often referred to simply as butts.

Carpet Shim

A spacer block used under a doorsill to raise the sill an appropriate amount if carpet is used, so the door clears the carpet when opened.


A horizontal or vertical molding, which accents or trims edges of doors and windows to the surrounding walls.


Sealant, used to seal against air and water leakage through the joint or recess.


Facing or jacket which works as a protection against weather and provides a finished appearance. Cladding may be painted metal, plastic, or a heavy coating applied by the manufacturer.

Clear Jambs

Natural wood door frames, without paint or primer applied, and which appears to be made of full-length pieces of stock, without joints or knots.

Closed-Cell Foam

Sponge-like material, usually used in gaskets and weather-stripping which compresses into joints, but absorbs little water.

Closer Block

An inside reinforcement, usually placed across the top edge of a door, to enable firm fastening of self-closing hardware.

Continuous Sill

A sill used for a type of door and sidelite unit in which the unit has full-width top and bottom frame parts, and an internal post(s) separating sidelites from the door.

Corner Plug, Corner Seal Pad

A small part, usually made of resilient material used to keep water from getting between the door edge and the jambs, adjacent to the bottom gasket.

Cove Molding

Molded piece of wood with concave profile used where doors meet a wall, or frame.


A large through-hole, near the edge of a door panel, which houses a cylinder lock-set or deadbolt latch.

Cylinder Lock

Lock hardware that mounts into a door which has been prepared with a bore hole(s).


A machined or sawn rectangular groove cut into a board or part so that a matching piece can be fitted into it to form a joint.

Deadbolt Spacing

The distance between the cylinder lock to the bore for the deadbolt lock.

Door Hand

The door hand is the description of which way the door opens.


Piece of Glass within door, used as a panel(s).


Insulated glass- two panes of glass separated with a sealed airspace between.

Drip Strip

In exterior doors, a fitting used across the outside face of the door adjacent to the bottom edge. It is used to divert cascading rain away from the door bottom edge and away from the door/sill joint.

Drywall Opening

A rectangular opening in a wall, usually an interior wall, prepared to the size necessary to receive a pre-hung door assembly.

Dummy Cylinder

A lock without a latch, typically used for the passive door panel of a double door unit, so that the hardware appears equal to that used on the active panel.

Electric Strike

A mechanism, which allows a switch to open the latch of a door.

End Seal Pad

A closed-cell foam piece, about 1/16-inch thick, in the shape of a sill profile, fastened between the sill and the jamb to seal the joint.


A stamped decorative plate. Used to trim the shaft of a door knob, deadbolt latch or the opening where the shaft or latch adjoins the face of a door.


The plated or solid metal trim piece, that is housed flush into the edge of a door.

Faceplate Mortise

The pocket in the edge of the door that is mortised to the door. Highly secure.

Finger Joint

A way of joining short sections of board stock together, end to end to make longer stock.

Fire Door

A door which has been tested to contain the spread of fire from one room or occupancy area to another. Fire doors are listed and labeled to show their ratings in terms of time.


A type of glazed door which has its glass perimeter moldings flush with or set down from the face of the surrounding door.


Rigid foam is used as the insulating and binding core for doors. Flexible foam is sometimes used as a gasket around door openings.

Foot Bolt

A steel pin housed in a bottom edge of door or astragal with a latch mechanism, which can be driven down into a receiver socket or hole in the floor or threshold. It allows the door to be better secured when closed.


The perimeter to which the door is hinged and latched. See jamb.


The elastic material used to seal glass to a surrounding frame.


A removable face-mounted assembly of thin wood or plastic pieces, which when in place, gives the lite or insert a patterned multi-pane look.

Grooved Glass

Glass, which has been decorated with abrasively routed recesses.


A term, which describes or determines the direction of swing of a door when opening.

Head Bolt

A steel pin housed in a door top edge or astragal. See foot bolt.

Head, Head Jamb

The horizontal top frame member of a door assembly.

Header Clearance

The clearance between the top edge of the door and the head jamb.


An assembly of metal plates and a cylindrical metal pin, which when fastened to a door edge and to a doorframe, allow the door to swing or rotate in its frame.

Hinge Sizes

The distance across the hinge, measured parallel to the hinge pin.

Hinge Stile

The full-length vertical pane of a door, at the side or edge of the door, which fastens to its frame with hinges.


A term for a door panel fixed in its frame that is not operable.

Insulated Glass

A glass assembly of multiple full-lite pieces, separated by an airspace/ perimeter spacer and sealed as a unit.


When the hinged door panel is opened, the panel swings into the building.


A vertical perimeter frame of a door unit.

Jamb Jack

A fastener device for fixing a door frame to a wall structure which allows the space or margin between the frame and the structure opening to be varied by turning the fastener screw.

Jamb Stop

In interior door frames the stop is the material attached to the jamb to which the door closes against. In exterior door-frames, it is the molded-in rebate surface of the jamb against which door panels close and seal.


A thin slot cut into an exterior jamb, that weather-stripping can be inserted.

King Stud

In a wood-framed rough opening, the stud which runs full height from floor plate to ceiling plate where trimmer stud attaches.


The feature of a hinge where the hinge leaf is cut for two or three projections which wrap and form a barrel or socket for the hinge pin.


A thin sheet of wood or plastic that is bonded with adhesive to a core or substrate which creates a decorative and usable surface.

Latch Bore

The hole drilled into the edge of a door to accept the door latch lock hardware.


A term which can apply to a door or hinge and which defines a part of the assembly which can swing on a pivot. Butt hinges have two leaves.


An assembly of glass and a surrounding frame.

Lock Block

A rectangular block of wood or other solid material, placed inside a door assembly at the lock side edge, which reinforces the assembly when the lock hardware is installed.

Lock Bore

For cylindrical lock-sets, the large through hole near the door panel’s lock edge into which the lock mechanism is placed and installed.

Lock Height

The dimension from the top of the door to the center line of the lock bore.

Lock Stile

In insulated door assemblies, the full-length part which makes up the lock edge of the door panel.

Low-E Glass

Glass which has been factory coated with a thin layer of material which acts to absorb and reflect heat and UV rays.


An angled cut across the end of a lineal part, usually done to join with a similarly cut part at a corner. Most typically used in casing.


A recess cut into the surface or edge of a part, usually for the purpose of housing hardware such as hinges, latch plates etc.

Mortise-Type Lock

A lock-set, which is housed into a deep recess cut into the edge of a door.


A short term for mullion. Used to describe the edge-joining of two door units or sidelites together.


A post or divider which runs from sill to frame top in multi-panel doors, or sidelite assemblies.

Multiple Extension Unit

In patio door assemblies, a fixed door panel in a separate frame, edge-joined to a patio door unit to add another glass panel to the installation.


In glazed lite assemblies, thin vertical and horizontal divider bars, which give the lite a multi-paned look. Muntins may be part of lite frames, and on the outside surface of the glass, or assembled between glass in insulated glass units.

NRP Hinge

An abbreviation for a hinge with a non-removable pivot pin. NRP hinges are used when exterior doors swing out, as a security feature. The fixed pins make it impossible to remove a door by driving out pivot pins.

Open-Cell Foam

A foam material which has passageways between cells. Open-cell foam will absorb and retain water.


An exterior door assembly in which the door panel swings outside the building.

Passage Lock

A lock-set, which will retain a door close, but which cannot be locked.


In a double or two-panel door assembly, the door which usually remains closed and fixed by bolts at top and bottom.


A decorative molding applied to the surface of a flush door, to give the appearance of a raised-molding design.


Abbreviation for polyvinyl chloride, a plastic material used to make molded or extruded parts.


A number which describes in relative terms the ability of a material or assembly to resist the flow or transmittance of heat. Assemblies or materials with high R-values are better insulators than those with lower R-values.

Rabbet, Rebate

A groove or step cut along the length of the edge of a piece of wood that is to be joined to another with a corresponding tongue or ledge cut into it.


In stile and rail doors, horizontal pieces at the top and bottom edges at intermediate points, connecting the stiles together.


The offset or space between edges of parts.


A term which describes the part of an adjustable sill which can be moved up or down by turning adjusting screws.

Rough Opening

A structurally-framed opening in a wall for a door or window.

Safety Glass

Glass which when broken, shatters into small pieces without sharp edges.


Elastic material pumped or trawled into a joint to prevent water penetration.


A thin piece of material used between parts of an assembly to change and fix the distance between parts, when they are fastened.


A fixed narrow panel, installed next to a door panel, for decorative purposes.

Slide Bolt

The part of an astragal assembly which places bolts into frame heads and sills. It is for fixing passive doors closed.


In stile and rail doors, the vertical pieces on both sides that connect the rails together, enabling lock, latch and hinge mortising to be done.

Stile and Rail Doors

A type of door constructed without a door skin, so that the vertical and horizontal members are visible.


A metal part with a hole or recess for receiving a door latch. It has a curved or ramped face so that a spring-loaded latch contacts it when closing.


The base or core material in an assembly of parts. The full-length wood or composite part of the sill.

Tempered Glass

A glass sheet, which has been strengthened by heat processing.


A pattern used to machine-cut a precise hole or recess into a door or frame part.

Thermal Break

A feature of a door/frame assembly which separates metal or glass exposed to outside temperatures from coming into contact and transmitting heat to or from inside-exposed parts.


Another term for sill. The horizontal part of a door assembly, fixed under the door panel and bearing on the floor.


A framed glass assembly mounted atop a door assembly.

Trimmer Stud

In a wood-framed rough opening, the stud or framing member which runs vertically from the sub-floor to the structural header member, into which a door frame is fastened.


An insulated glass assembly made of three thicknesses of glass, with air spaces between.


A thin film or facing, adhesively bonded to a core or substrate, which makes up the exposed and decorative face of an assembly.


A permanent curvature or deviation from straightness.

Wired Glass

Glass made for use in fire doors, which has embedded wires which bind the glass, and permit the glass to remain solid when exposed to fire.