Active: In paired or double doors, the hinged door leaf which is primarily operable.

Astragal: The post-type fitting on the latch-side edge of a set of double doors, which covers the margin between doors when they are closed, and which houses or contains the weatherstrip.

Boot: A term used for the rubber part at the bottom or top end of an astragal, which seals the door frame.

Box-framed: A door and sidelite unit that is framed as separate units, with heads and sills separate. Box-framed doors are joined to box-framed sidelites.

Brickmould: A molding used to trim the outside edge of a door frame. Brickmould is most often applied to prehung units.

Carpet Shim: A spacer block used under a door sill to raise the sill so the door panel clears the carpet when opened.

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

Clear Jambs: Natural wood door frames without joints or knots.

Core: The center section or part of a door or door part.

Corner Seal Pad: A small part, usually made of resilient material, used to seal water from getting between the door edge and the jambs.

Cylinder lock: Lock hardware which mounts into a door which has been prepared with a bored hole or holes through the face and into the edge. Also called a cylindrical lock.

Deadbolt: A latch used to secure a door closed, the latch being driven from the door into a receiver in the jamb or frame.

Doorlite: An assembly of frame and glass panel, which when fitted to a door in a formed or cut-out hole, creates a door with a glass opening.

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

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

Faceplate: The plated or solid metal trim piece, usually about 1 x 2-1/4 inches, housed flush into the edge of the door, through which projects the latch of a passage lock or deadbolt.

Foot Bolt: A steel pin housed in a door bottom edge or astragal, with a latch mechanism, which can be driven down to project into a receiver socket in the floor or threshold, to secure the door when closed.

Frame: In door assemblies, the perimeter members at the top or sides, to which the door is hinged and latched. See jamb.

Grille: An assembly of wood or plastic pieces used to give the doorlite a patterned multi-pane look.

Handing: 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 of a door assembly.

Hinge: Metal plates with a cylindrical metal pin that fastens to a door edge and door frame to allow the door to swing.

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

Inswing: A term used to describe an exterior entry door which swings into a home or building. See also Outswing.

Jamb: A vertical perimeter frame part of a door system.

Kerf: A thin slot cut into a part with a molder or saw blade. Weather strip is inserted into kerfs cut into door jambs.

Latch: A moveable, usually spring-loaded pin or bolt, which is part of a lock mechanism, and engages a socket or clip on a door jamb, keeping the door closed.

Leaf: A term which can apply to a door or hinge and which defines a part of the assembly which can swing on a pivot.

Lite: An assembly of glass and a surrounding frame, which is assembled to a door at the factory.

Lock Block: A rectangular block of wood placed inside a door at the lock side edge, which reinforces the assembly when the lock hardware is installed.

Lock Bore: For cylindrical locksets, the through hole, usually 2 1/8 inches in diameter, bored near the door panel’s lock edge, into which the lock mechanism is placed and installed.

Lock Stile: In wood stile and rail doors, the full length wood piece, 4 to 6 inches wide, at the lock edge of the door.

Mortise: A recess cut into the edge of a door for the purpose of housing hardware such as hinges and lock parts.

Mortise-Type Lock: A lockset which has a rectangular-shaped mechanism, which is housed into a deep recess cut into the edge of a door.

Mull: A short term for mullion. Used to describe the joining of two doors together, or the joining of a door to a sidelite unit.

Mullion: A post or divider which runs from sill to frame top in a multi-panel door or door and sidelite assembly. In stile and rail doors, the vertical wood parts which separate panels.

NFRC: The National Fenestration Ratings Council, an industry association which sets standards for testing, rating and labeling doors and windows with thermal information.

NRP Hinge: A hinge with a non-removable pivot pin 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.

Outswing: An exterior door assembly in which a door panel swings outside the building. See also Inswing.

Passive: In a double door assembly, the door which remains closed and fixed by bolts at top and bottom.

Prehung: A door assembled in a frame (jamb) with sill, weather stripping and hinges and ready to be installed into a rough opening.

Rail: In insulated door panels, the part, made of wood or a composite material, which runs inside the assembly, across the top and bottom ends. In stile and rail doors, horizontal pieces at top and bottom edges, and at intermediate points,  which connect and frame between the stiles.

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

Rough Opening: A structurally-framed opening in a wall which receives a door unit or window.

Screen Track: A feature of a door sill or frame head which provides a housing and runner for rollers, to allow a screen panel to slide from side to side in the door.

Self-Locating Hinge: A hinge with indexing or locating tabs to aid in exact placement against a door edge.

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

Sidelite: A fixed narrow panel with glass, installed next to a door panel, for decorative purposes.

Sill: The horizon base of a door frame which functions with the door bottom to seal out air and water.

Slide Bolt: Part of an astragal at the top or bottom, which bolts into frame heads and sills for fixing passive door panels closed.

Stile: In insulated door panels, the full-length parts, usually wood, which make up the long edges. In stile and rail doors, the vertical edge parts.

Strike: A metal part for a hole for a door latch, and a curved face so a spring-loaded latch contacts it when closing. Strikes are fit into mortises in door jambs and fastened with a screw.

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

Transom: A framed glass assembly mounted above a door unit.

Weatherstripping: A narrow strip of material installed around a door which provides a seal against air and water infiltration.