Industry Terminology

Think of this as your door dictionary. Refer to this section to familiarize yourself with common terms you may come across while making your door selection.

The following definitions are extracted from WDMA I.S.lA-11, Industry Standard for Architectural Wood Flush Doors and WDMA I.S.6A-1 1, Industry Standard for Architectural Stile and Rail Doors.

*These definitions are not included in current industry standards, however, they are common industry terms.

  • a
  • Adhesive Performance Levels

    The Standard Specification for Adhesives used in Nonstructural Glued Lumber Products, designated D3110-72 by the American Society for Testing and Material (ASTM), establishes acceptable performance levels for glues or adhesives to be used in nonstructural glued lumber products. Such products include, but are not limited to interior and exterior mouldings, window and door stock, and glued lumber panels. In this specification adhesives are classified on the basis of two performance levels, wet-use and dry-use.

  • Astragal

    This moulding includes two different types, a T-Astragal and a Flat Astragal. Both are attached to one of a pair of doors to keep the other door from swinging through the opening. The flat astragal, can also be used for decorative purposes to cover a joint or separation.

  • b
  • Back Band

    A rabbetted moulding used to surround the outside edge of casing. Adding a back band will add depth to the casing where it meets a base moulding that is thicker than just the casing.

  • Backed Out

    To groove or remove a portion of the wood on the unexposed face of a wood member to better fit over irregular surfaces; also called, hollow-backed.

  • Base

    Applied where floor and walls meet, forming a visual foundation. Protects walls from kicks and bumps, furniture and cleaning tools.

  • Base Cap

    A decorative member installed flush against the wall and the top of an S4S baseboard. Also a versatile panel moulding.

  • Base Shoe

    Applied where base moulding meets the floor to protect the base moulding from damage by cleaning tools and conceals any uneven lines or cracks where base meets the floor.

  • Batten

    A symmetrical pattern used to conceal the line where two parallel boards or panels meet.

  • Bullnose

    The rounded end or edge of a board such as a stair tread or shelf.

  • c
  • Cased Opening

    An interior opening without a door but wrapped with a jamb and casing.

  • Casing

    Used to trim both sides of doors, windows, and large openings such as cased openings.

  • Chair Rail

    An interior moulding applied about a third up the wall from the floor, paralleling the base moulding and encircling the perimeter of a room. Originally used to prevent chairs from marring walls. Used today is as a decorative element or a divider between different wall covering such as wallpaper and paint or wainscoting.

  • Champher Strip

    A triangular moulding often used in concrete forming work to support the corners of the forms.

  • CLF

    Abbreviation for “hundred lineal feet.”

  • Coped Joint

    A joint at the meeting of moulded members.

  • Coping

    Carpentry process by which a moulding such as a crown is sawn on the adjourning end to fit over the face profile of the second member. Used where mouldings join at 90-degree angles on a wall or ceiling installation.

  • Corner Guard

    Inside or outside corners used to protect the corners, cover ragged edges or uneven joints where wall coverings painted or contrasting surfaced walls.

  • Cornice

    Exterior trim used at juncture of outside wall and roof. Also describes interior trim used where walls and ceiling meet (crown, cove, bed moulding).

  • Cove

    A concave profile used at corners, particularly as a ceiling cornice. Small coves may be used as an inside corner guard.

  • Crown and Bed Mould

    Used where walls and ceiling meet. Crown mouldings are used to cover larger angles. Crowns are always “sprung” while beds are either “sprung” or plain. A “sprung” moulding has the interior corner beveled off to better fit a right angle joint.

  • Cut Stock

    Small pieces of surfaced, partially worked, or rough lumber, available in specified sizes suitable for manufacturing into millwork products.

  • Cutter Head

    Fitted with moulding knives, cutter heads are installed in moulders where they rotate at high speeds to shape the moulding profiles.

  • d
  • Dentil

    A series of small square blocks uniformly spaced and projecting like teeth. Often used in a cornice or mantel treatment.

  • Dimensional Stability

    The ability of material to maintain its original dimensions under variations of temperature, moisture, and physical stress.

  • Door Frame

    A group of wood parts machined and assembled to form a door enclosure from which and exterior door is hinged.

  • Door Jamb

    A group of wood parts machined and assembled to form a door enclosure from which and interior door is hinged.
    See also: split jamb; flat jamb; header; hinge jamb; rabbeted door jamb; strike jamb

  • Door Trim

    Trim for a door opening usually consisting of casing.

  • Drip Cap

    Applied over the exterior window and door frames, to keep water from seeping under the siding and directing it away from the door or window. Also makes an attractive contemporary interior door and window casing.

  • Drip Groove

    A semicircular grove on the underside of the drip cap or the lip of a window sill which prevents water from running back under the drip or sill.

  • Dry-Use Adhesive

    An adhesive capable of developing sufficient strength and durability to make the glued lumber product serviceable under ordinary conditions of nonstructural use, when the Equilibrium Moisture Content (EMC) does not exceed 16% and the temperature may reach 165 degrees Fahrenheit (74 degrees Celsius) for as long as 6 hours during shipment or no greater that 140 degree Fahrenheit (60 degrees Celsius) continuously during service.

  • e
  • Eased Edge

    A slightly rounded corner which reduces splintering.

  • Exterior Trim

    Trim used on the exterior of a structure.

  • f
  • Face

    Outer or exposed surface from which grade is determined.

  • Face Measure

    The measurement across the face of any wood part exclusive of any solid mold or rabbet.

  • Factory or Shop Lumber

    An industrial lumber grade.

  • Fillet

    A narrow band of wood between two flutes in a wood member; a flat, square moulding separating other mouldings.

  • Finger Joint

    A joint made by cutting away interlocking fingers in the ends of two adherends and bonding the adherends with the cut areas fitted together to form longer pieces.

  • Finger Jointer

    Machinery which cuts, glues and joins the fingers in fingerjointed lumber or cut-stock for mouldings and millwork.

  • Finish

    With multiple meanings, it can mean the interior or exterior finish of a structure, the finish or actual size of a piece of lumber, the protective coating given a wood member, or the select grades of softwood lumber.

  • Flat Jamb

    A four-sided jamb surface where a separate wood stop may be applied. Also referred to as a one-piece jamb.

  • Flute

    A long, rounded groove machined along the grain of a wood member.

  • g
  • Glass Bead

    Used to hold glass in place.

  • Grade

    Wood moulding and jambs are available in two standard grades.
    See also: N-Grade; P-grade

  • Grain Printed

    A method of pre-finishing mouldings where the moulding receives a color coating, is printed with a wood grain, and top-coated for durability.

  • h
  • Half Round

    A moulding with a profile that is a half circle with many purposes such as shelf edge, panel mould, screen mould or a bead.

  • Hand Rail

    Used as a hand support in a stairwell.

  • Hardwood

    Hardwoods are one of the botanical groups of trees that have broad leaves in contrast to the needle-like leaves of the conifers or softwoods.

  • Header

    The horizontal member forming the top of the opening.

  • Hinge Jamb

    Side jamb in which the door hinges (butts) are applied.

  • i
  • Interior Trim

    Trim used on the interior of a structure; sometimes referred to as interior finish.

  • j
  • Jamb Liner

    A small strip of wood, either surfaced four sides or tongued on one edge, which, when applied to the inside edge of a window jamb, increases its width.

  • Joints

    See: Coped Joint; Dado joint; Finger Joint; Laminate Joint; Miter Joint

  • k
  • Kerfing

    Longitudinal saw cuts of machined grooves of varying depths (dependent on the thickness of the wood member) made on the unexposed faces of millwork members to relieve stress and prevent warping.

  • Knee Wall Moulding

    A crown like moulding suitable for installation at oblique joints.

  • Knots

    A portion of a branch or limb that has become incorporated in a piece of lumber. In lumber, knots are classified as to form, size, quality and occurrences. A red knot is one that results from a live branch growth in the tree and is inter-grown with the surrounding wood. A black knot is one that results from a dead branch which the wood growth of the tree had surrounded.
    (a) A pin knot is not over 1/2″.
    (b) A small knot is not over 3/4″.
    (c) A medium knot is not over 1-1/2″.
    (d) A large knot is over 1-1/2″.
    (e) A sound knot contains no decay. It may be red or black.
    (f) A tight knot is so fixed by growth, shape or position that it retains its place in the piece. It may be red or black.
    (g) A “loose” or “not firmly fixed” knot is one not held tightly in place by growth, shape or position.
    (h) A “fixed” knot will retain its place in dry lumber under ordinary conditions but can be moved under pressure through not easily pushed out.

  • l
  • Lattice

    Originally used in trellis work, this small plain, S4S moulding is among the most versatile of profiles.

  • Lineal Foot

    A measure of length stated in feet or metric.

  • m
  • Millwork (woodwork)

    Products primarily manufactured from lumber in a planning mill or woodworking plant. Includes; mouldings, door frames and entrances, blinds and shutters, sash and window units, doors, stair-work, kitchen cabinets, mantels, china or corner cabinets, and porch work.

  • Millwork Estimate

    The number, sizes, types, and cost of millwork items required for a construction job or structure.

  • Miter Box

    A tool, often fitted with a back saw, which is used to cut accurate angles for tight fitting miter joints.

  • Miter Joint

    The joining of two members at an angle that bisects the angle of junction. In mouldings this is most often a 45 degree angle.

  • Moisture Content

    The weight of the water in wood expressed in percentage of the weight of the oven-dry wood.

  • Moulded

    Worked into a form of shape and referring to a wood member other than those “surfaced four sides.”

  • Moulder (sticker)

    A woodworking machine designed to run mouldings and other wood members with regular or irregular profiles.

  • Moulding Series

    Mouldings of a certain pattern and size to which individual numbers have been assigned.

  • Mullion Casing

    The strip which is applied over the window jambs in a multiple opening window. Sometimes called a panel strip and used for decorative wall treatments.

  • n
  • N-Grade

    Intended for natural or clear finishes and the exposed face must be of one single piece.

  • Nosed

    A rounded edge.

  • o
  • Occasional Pieces

    Means not more than 10% of the pieces in a parcel or shipment.

  • Ogee or O.G.

    Having an “S” shaped or reverse curve profile; the “ogee” arch was pointed with an “ogee” curve on each side.

  • Ovolo

    A convex profile usually a quarter section of circle similar to the profile of quarter round.

  • p
  • P-Grade

    Intended for opaque paint finishes or overlays and can be fingerjointed and or edge glued.

  • Packaged Millwork

    The wrapping or packaging of millwork items. May be in paper cartons or shrink wrapped in plastic film.

  • Pairs

    Term used to describe the two side members of door jambs, frames, or casing trim.

  • Panel Divider

    A moulding which separates two vertical wood panels along their common edges.

  • Parting Stop

    A small strip of wood let into the plough of the jambs of a double hung check-rail window frame to separate the top sash from the bottom sash; also parting bead, parting strip, or check strip.

  • Picture Frame Moulding

    Rabbeted moulding forming a frame for pictures.

  • Picture Mould

    Used to support hooks for picture hanging. Applied around a room’s circumference near the ceiling line.

  • Piece

    A term used to describe cut-to-length mouldings sold by the piece rather than per hundred lineal feet.

  • Pilaster

    A rectangular, circular or semi-circular member used as a simulated column in entrances and other door openings and fireplace mantels; usually contains base, shaft and capital.

  • Pitch

    An accumulation of resinous material.
    (a) Light pitch is the light but evident presence of pitch.
    (b) Medium pitch is a somewhat more evident presence of pitch than is the light.
    (c) Heavy pitch is a very evident accumulation of pitch showing by its color and consistency.

  • Pitch Streak

    A well-defined accumulation of pitch in the wood cells in a more or less regular streak. It should not be confused with dark grain.

  • Plant on Moulding

    A moulding applied to a surface which projects or remains above it. An applied moulding.

  • Plinth Block

    A block at the base of a pilaster; a block of wood placed at the bottom of side door casing to terminate the casing as well as the base. Since the door casings and bases are moulded, plinth blocks offer a good looking, sturdy member which solves the problem of joining casing and base mouldings with different profiles. Plinth blocks are thicker and wider than the abutting members.

  • Plow

    A rectangular slot of three surfaces cut with the grain of the wood.

  • Pocket

    A well-defined opening between the rings of annual growth which develops during the growth of the tree. It usually contains pitch or bark.

  • Prefinished

    Millwork with an applied finish coating. May be grain printed, vinyl wrapped, toned or in a solid opaque color.

  • Prehung Door Unit

    A precut and assembled unit consisting of a wood door with the locking or passage hardware that is hung on hinges in a wood frame. The wood frame includes the one or two piece jamb either in adjustable or pre-ordered widths as well as the door stop mouldings and casings.

  • Preservative

    Any substance that, for a reasonable length of time, will prevent the development and action or wood-destroying fungi, borers of various kinds and other harmful insects that deteriorate wood.

  • Prime Coat

    The first coat of paint in an application that consists of two or more coats; also refers to the paint used for such an initial coat; priming; primer; paint-primed.

  • Primed

    A wood part which has been coated with paint primers either in the factory or on site.

  • q
  • Quarter Round

    Versatile quarter round may be used as a base shoe, inside corner moulding or to cover any 90 degree recessed junctures. Often used to cover the line where roof and siding meet on exteriors.

  • r
  • Rabbet

    A rectangular cut where two surfaces are cut on the edge of a member parallel with the grain. On a door jamb the rabbets would form a built-in stop on the face of the jamb.

  • Rabbeted Door Jamb

    A jamb with a rabbet on one or both edges. If both edges are rabbeted, “double-rabbeted door jamb.” If one edge is rabbeted, “plain rabbeted door jamb.”

  • Raised Moulding

    A moulding not on the same level or plane as the wood member or assembly to which it is applied; as contrasted to “flush moulding.”

  • Rake Moulding

    A moulding applied to the rake or the exposed inclined ends of a gable roof; term is sometimes applied to any moulding installed in a direction other than horizontal or vertical; also barge moulding.

  • Random Lengths

    Unspecified lengths as contrasted to “specified lengths.”

  • Return

    Continuation in a different direction of a moulding or projection, usually at right angles.

  • Reveal

    That portion of the moulding and or jamb that is exposed when two members are joined, such as when casing is applied against the jamb.

  • Rough Lumber

    Lumber that has not been dressed or surfaced but which has been sawed, edged and trimmed at least to the extent of showing saw marks in the wood.

  • Round Edge

    The corners of a piece shaped to a radius; generally implies a greater radius than for an “eased edge”; shaped primarily for appearance.

  • Running Trim

    Interior of exterior trim ordered in linear of lineal measurement and which extends for runs around the perimeter of a room or structure; as opposed to standing trim.

  • s
  • Sapwood

    Outer layers of growth between the bark and the heartwood which contain the sap.

  • Scotia

    A deep concave moulding more than 1/4 round

  • Screen Moulding

    A small moulding which covers the seam where screening is fastened to the screen frame.

  • Screen Stock

    A S4S moulding originally used in the construction of screens. Used extensively in cabinet work and finished carpentry where a clear strip is required. Many times referred to as S4S stock.

  • Sets

    Mouldings or jambs sold as a unit or two sides and a header, usually for installation around a door opening.

  • Shelf Cleat

    A moulding commonly used in closets to support the shelves, also shelf strip.

  • Shingle/Panel Mould

    A decorative patter, originally used to trim out raised panel wall construction. It is most useful fabricated as a frame, surrounding attractive wall covering for a paneled effect on walls.

  • Shorts

    A general term for lumber and moulding lengths under 6 feet.

  • Sill

    The horizontal member forming the bottom of a window or exterior door frame; as applied in general to construction, the lowest member of the frame of a structure, resting on the foundation and supporting the frame.

  • Smooth Sawn

    The surface is machined by fine saw work.

  • Softwood

    Softwoods are one of the botanical groups of trees that have persistent needle-like or scale-like leaves. Most softwoods are evergreens.

  • Solid Moulding

    Non-finger-jointed mouldings; solid length.

  • Specialty Millwork (architectural millwork)

    Millwork manufactured by special order to suit a particular job.

  • Specified Lengths

    Mouldings sold and shipped in lengths specified by the customer such as all “7 and/or 14-feet,” “8 and/or 16-feet,” “all 8-feet, ” etc.

  • Split Jamb

    A two (sometimes three) piece split jamb consisting of a rabbeted and adjusting jamb section for walls of varying thickness; the rabbeted jamb contains a plow to receive the tongue of the adjustable member.

  • Sprung

    The interior corner of a moulding “beveled off” to better fit a right angle joint; in contrast to non-sprung or plain moulding.

  • Stain

    A discoloration of the wood. Brown stain is due to a chemical reaction occurring in the drying of some species. Blue stain is cause by the growth of mould like fungi on the surface or in the interior of the wood prior to the time the wood is dry. The stain does not effect the strength of the wood, and the growth of the fungi stops once the wood is dry. Stain, in grading rules is defined as light, medium, and heavy. Light stain is so slight that it does not effect the appearance for natural finishes. Heavy stain is permitted only in paint grades.

  • Sticker

    A woodworking machine designed to run mouldings and other wood members with regular or irregular profiles.

  • Stock Millwork

    Millwork manufactured in a standard size, pattern and layout, readily available from a distributor’s inventory and ready for installation.

  • Stool

    A moulded interior trim member serving as a sash or window frame sill cap.

  • Stop

    In door trim, stop is nailed to the faces of the door frame to prevent the door from swinging through. As window trim, stop holds the bottom sash of a double-hung window in place.

  • Straddle moulding

    A two member decorative glass bead-like moulding around the light opening of a flush door.

  • Strike Jamb

    The jamb opposite the hinge jamb on which the lock or strike plate is installed.

  • t
  • Tear Drop

    A term given to mouldings with a gradual curved profile.

  • Tenon

    A projection tongue-like part of a wood member to be inserted into a slot (mortise) of another member to form a “mortise and tenon joint.”

  • Toned

    Moulding pre-finished by staining and top-coating.

  • Torus

    A large bead; opposite of scotia; rope like moulding.

  • Trim

    Millwork, primarily mouldings and/or trim to finish-off (trim around) windows and door openings, fire-places, walls and other members.
    See also- Door Trim; Exterior Trim; Interior Trim; Running Trim; Window Trim

  • Trimbacks

    Odd lengths developed in the manufacture of cut-to-length finger jointed mouldings.

  • Trimming Out

    Installing “trim”; sometimes refers to interior finish.

  • v
  • Vinyl Wrapped Moulding

    A wood moulding pre-finished by wrapping with vinyl film, either in wood grains and colors or solid un-grained color.

  • w
  • Wainscot

    A lower interior wall surface (usually 3 to 4 feet above the floor) that contrasts with the wall surface above it; an interior wall composed of two different interior wall surfaces on above the other.

  • Wainscot/ Plycap Moulding

    Covers and beautifies plywood’s/ wainscot’s upper edge or rough sandwich edge in installation where it is exposed to view.

  • Wane

    Bark or lack of wood from any cause, except eased edges, on the edge or corner of a piece of lumber.

  • Warp

    Any deviation from a true or plane surface, including bow, crook, cup and twist and any combination thereof. Warp restrictions are based on the average form of warp as it occurs normally, and any variation from this average form, such as short kinks, shall be appraised according to its equivalent effect. Pieces containing two or more forms shall be appraised according to the combined effect in determining the amount permissible. Warp may be classified as very light, light, medium, and heavy.

    Bow is a deviation flatwise from a straight line drawn from end to end of a piece. It is measured at the point of greatest distance from the straight line. The amount permitted according to the drade is as follows: If under 2″ thick, three times as much as crook permitted for 2″ faces. If 2″ thick and under 3″, twice as much as crook permitted for 2″ faces. If 3″ thick and over, the same as the amount of crook permitted for that thickness.

    Crook is a deviation edgewise from a straight line drawn from end to end of a piece. It is measured at the point of greatest distance from the straight line.

    Cup is a deviation in the face of a piece from a straight line drawn from edge to edge of a piece. It is measure at the point of greatest distance from the straight line.

    Twist is a deviation flatwise, or a combination of flatwise and edgewise, in the form of a curl or spiral, and the amount is the distance an edge of a piece a one end is raised above a flat surface against which both edges

  • Water-Repellent Preservative

    A solution of a water-repellent and wood preservative used to prevent decay and resist insect damage; stabilizes wood.

  • Wet-Use Adhesives

    An adhesive capable of producing sufficient bond strength to make the glued lumber product serviceable under nonstructural use while exposed at an Equilibrium Moisture Content (EMC) of 16% or greater and the temperature may reach as high as 165 degrees Fahrenheit (74 degrees Celsius) at times during service.

  • Window Trim

    The moulding and/or trim necessary to “finish” or “trim” a sash or window frame.

  • WM

    Stand for the Wood Moulding Association whose members always manufacture to the industry’s highest standards using renewable resources.