Doors & Trim Glossary

A

Specialty Doors

Acoustic Door

A door assembly designed and tested to reduce the transmission of airborne sound.

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Doors

Active Door

The leaf of a pair of doors that is normally used as the primary operating door.

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Doors

Astragal

A vertical moulding or seal applied to the meeting edge of a pair of doors.

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B

Trim & Moulding

Backband

A decorative trim profile installed behind door or window casing to add depth and visual definition.

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Hardware

Backset

The distance from the edge of a door to the centerline of the bore or latch.

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Hardware

Ball Bearing Hinge

A hinge that uses bearings in the knuckles to reduce friction during door operation.

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Doors

Barn Door

A sliding door mounted on exposed hardware that moves along a track outside the wall.

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Trim & Moulding

Base Cap

A smaller decorative moulding applied to the top edge of baseboard to create a layered profile.

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Trim & Moulding

Baseboard

Trim installed along the bottom of interior walls where the wall meets the floor.

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Trim & Moulding

Beaded Casing

Door or window casing featuring a bead or rounded linear detail along the profile.

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Doors

Bifold Door

A door made of two or more hinged panels that fold together to open within the doorway.

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Materials

Birch

A hardwood species commonly used for doors, veneers, and trim, with a relatively fine and even grain.

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Doors

Bottom Rail

The lower horizontal rail of a stile-and-rail door.

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C

Trim & Moulding

Cap Moulding

A decorative moulding used to finish the top edge of a panel, wall treatment, or other trim assembly.

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Doors

Carved Door

A door with decorative patterns or profiles routed or carved into its face.

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Trim & Moulding

Chair Rail

Horizontal wall moulding traditionally installed around a room at approximately chair-back height.

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Doors

Commercial Door

A door specified for commercial or institutional environments with requirements that may differ from typical residential applications.

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Hardware

Continuous Hinge

A full-length hinge that runs along most or all of the door edge and frame.

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Trim & Moulding

Corner Block

A decorative block used at a trim intersection to create a deliberate architectural transition.

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Trim & Moulding

Crown Moulding

Decorative moulding installed where a wall meets the ceiling.

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D

Hardware

Door Bore

A drilled hole in a door for installing a cylindrical or tubular lockset and related hardware.

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Trim & Moulding

Door Casing

Trim that surrounds a door opening and covers the joint between the jamb and wall.

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Materials

Door Core

The internal material or construction that forms the main body of a door beneath its face or veneer.

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Frames & Jambs

Door Frame

The fixed structure around a door opening that supports the jambs and door assembly.

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Installation

Door Handing

The designation used to describe which side of a door is the hinge side and how the door is configured to operate.

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Frames & Jambs

Door Jamb

The vertical and horizontal members that form the sides and top of a door opening and support the door.

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Doors

Door Slab

The door itself without the surrounding jamb, frame, or preinstalled hardware.

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Frames & Jambs

Door Stop

A moulded or applied strip on the jamb that limits the door's closed position.

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Installation

Door Swing

The direction and arc in which a hinged door moves when it opens.

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Installation

Door Thickness

The dimension measured across the depth of a door slab from one face to the other.

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Doors

Double-Acting Door

A door designed to swing in both directions from the closed position.

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Doors

Double Door

A doorway fitted with two door leaves that meet at the center or operate as a paired set.

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Doors

Dutch Door

A door divided horizontally so the upper and lower sections can operate independently.

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E

Materials

Edge Banding

A narrow strip of material applied to the edge of a panel or door component to cover the exposed substrate.

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Materials

Engineered Wood

Wood-based material manufactured from fibers, particles, veneers, or strands bonded into a controlled panel or component.

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F

Materials

Face Veneer

The visible layer of wood veneer applied to the front or back face of a door or panel.

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Installation

Finished Opening

The completed, trimmed opening available for the door assembly after framing and wall finishes are installed.

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Specialty Doors

Fire-Rated Door

A door assembly tested and rated to resist fire for a specified period under defined testing conditions.

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Materials

Flat-Sawn

A common wood-cutting method that produces broad faces and pronounced cathedral grain patterns.

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Doors

Flush Door

A door with a flat, uninterrupted face rather than raised or recessed panels.

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Trim & Moulding

Fluted Casing

Door or window casing with repeated vertical grooves that create a textured architectural profile.

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Doors

French Door

A door with multiple glass panes or broad glazed sections, often used singly or as a pair.

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G

Materials

Grain Direction

The orientation of visible wood fibers in a door, veneer, trim piece, or moulding.

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H

Materials

Hardwood

Wood from broadleaf trees that is commonly used for durable doors, trim, flooring, and millwork.

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Frames & Jambs

Head Jamb

The horizontal jamb member across the top of a door opening.

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Frames & Jambs

Hinge Jamb

The side jamb where the door hinges are mounted.

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Hardware

Hinge Leaf

One of the two flat plates of a hinge that attaches to the door or frame.

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Hardware

Hinge Mortise

A recessed pocket cut into a door edge or jamb so a hinge leaf can sit flush with the surrounding surface.

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Doors

Hinge Stile

The vertical stile on the side of a door where hinges are mounted.

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Doors

Hollow Core Door

A lightweight interior door constructed around a hollow or lightweight internal core.

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I

Doors

Inactive Door

The leaf of a pair of doors that normally remains secured and is opened when additional width is needed.

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Doors

Interior Door

A door intended to separate spaces within a building rather than serve as an exterior entrance.

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Specialty Doors

Intumescent Seal

A material that expands when exposed to heat and is used to help protect gaps in certain fire-rated door assemblies.

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J

Frames & Jambs

Jamb Extension

A piece added to a door jamb so the jamb matches a wall that is deeper than the standard jamb size.

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K

Installation

Kerf

A narrow groove cut into a door or frame edge to receive a seal, weatherstrip, or other inserted component.

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L

Doors

Lite

A glazed opening or individual pane of glass incorporated into a door.

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Doors

Lock Stile

The vertical stile on the side of a door where the lock or latch hardware is located.

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Doors

Louvered Door

A door containing angled slats or louvers that permit airflow while providing some visual separation.

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M

Materials

MDF

Medium-density fiberboard, an engineered wood panel made from refined wood fibers bonded under heat and pressure.

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Materials

Mineral Core

A fire-resistant door core made from mineral-based materials and used in certain rated assemblies.

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Hardware

Mortise Lock

A lockset installed in a pocket cut into the door edge and body rather than mounted only through the face.

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Doors

Mullion

A vertical or horizontal member that divides adjacent glazed openings or panels.

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P

Materials

Paint Grade

A material or finish grade selected and prepared to receive an opaque painted finish rather than a transparent stain.

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Doors

Panel Door

A door made with one or more framed panels that create a traditional architectural face.

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Trim & Moulding

Panel Moulding

Narrow decorative moulding used to create framed wall panels and other architectural patterns.

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Materials

Particleboard Core

A manufactured wood core made from wood particles bonded together under pressure.

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Trim & Moulding

Picture Frame Moulding

Decorative narrow moulding used to create framed wall panels or picture-frame-style trim layouts.

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Doors

Pivot Door

A door that rotates on pivot hardware rather than conventional hinges mounted along the side edge.

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Trim & Moulding

Plinth Block

A decorative block installed at the bottom of a door casing where it meets the baseboard.

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Doors

Pocket Door

A sliding door that moves into a recessed wall cavity instead of swinging into the room.

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Materials

Poplar

A hardwood commonly used for paint-grade doors and interior trim because of its availability and workable characteristics.

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Doors

Prehung Door

A complete door unit supplied with the door slab installed in a jamb and typically equipped with hinges.

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Materials

Primed MDF

MDF moulding or millwork supplied with a factory-applied primer or coating for paint finishing.

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Q

Trim & Moulding

Quarter Round

A small quarter-circle moulding used to cover a joint or create a finished transition along a floor or wall.

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Materials

Quarter-Sawn

A wood-cutting method that produces prominent grain patterns and, in some species, distinctive ray or fleck figures.

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R

Installation

Rabbet

A rectangular recess cut along the edge of a board or frame member to receive another component.

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Doors

Rail

A horizontal member of a stile-and-rail door that helps form its structural framework and panel layout.

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Materials

Red Oak

A widely used hardwood with a pronounced open grain and warm, varied color.

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Installation

Reveal

A deliberate visible gap or offset between adjacent door or trim components.

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Materials

Rift-Sawn

A method of cutting wood to produce a relatively straight, consistent grain with reduced visible cathedral patterns.

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Trim & Moulding

Rosette

A decorative block used behind a door casing or around trim joints instead of a traditional mitered corner.

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Installation

Rough Opening

The framed wall opening prepared to receive a door or prehung door assembly before finish materials are installed.

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S

Doors

Shaker Door

A door with a simple, clean panel profile characterized by flat or minimally detailed panels and rails.

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Trim & Moulding

Shoe Moulding

A narrow trim profile used at the bottom of baseboard to cover small gaps between baseboard and flooring.

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Doors

Simulated Divided Lite (SDL)

A door glazing configuration that uses one or more larger panes of glass with applied or integrated bars to resemble individual lites.

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Doors

Sliding Door

A door that opens by moving horizontally along a track instead of swinging on hinges.

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Specialty Doors

Smoke Seal

A seal intended to limit the passage of smoke around a door assembly.

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Doors

Solid Core Door

A heavier interior door built with a dense core for added durability, feel, and sound control.

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Specialty Doors

Sound Transmission Class (STC)

A rating used to describe how well a building assembly reduces the transmission of airborne sound.

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Hardware

Spring Hinge

A self-closing hinge that uses an internal spring to return the door toward a closed position.

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Materials

Stain Grade

A material or finish grade selected for a transparent or semi-transparent finish that allows natural wood character to remain visible.

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Doors

Stile

A vertical structural member along the side of a stile-and-rail door.

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Trim & Moulding

Stop Moulding

A strip of moulding that creates a stopping surface for a door or frames another component.

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Frames & Jambs

Strike Jamb

The side jamb where the latch or strike hardware engages when the door closes.

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T

Doors

Top Rail

The upper horizontal rail of a stile-and-rail door.

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Doors

True Divided Lite (TDL)

A door glazing configuration in which individual glass panes are separated by actual structural bars or muntins.

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V

Materials

Veneer

A thin layer of real wood applied over a substrate or core to provide the appearance of a wood species.

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W

Trim & Moulding

Wainscoting

A decorative wall treatment consisting of panels, rails, stiles, or moulding applied over part of a wall.

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Materials

White Oak

A hardwood species known for its distinctive grain, durability, and relatively light natural color.

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Materials

Wood Movement

The natural expansion, contraction, and dimensional change of wood caused by changes in moisture content.

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