Common Industry Door Terminology
Active Door: The primary door used in a double door configuration. This door will contain the operational handle set.
Adjustable Threshold: A threshold that can adjust up or down to seal the door, also known as an adjustable sill.
Astragal (T-Astragal): A "T" shaped component that is attached to the inactive door. Astragals are kerfed for weather-stripping to seal the gap between the two doors. In addition, top and bottom flush bolts are mortised into the astragal to hold the inactive door in place.
Back-set: The distance from the edge of the door to the center of the lock bore hole.
Ball Bearing Hinge: A heavier-duty hinge equipped with ball bearings between the hinge knuckles to reduce friction. Mainly used with exterior doors to provide smoother and quieter operation.
Bottom Rail: The framework at the bottom of a door, also called the threshold.
Brickmould: A decorative moulding used to trim the outside edge of a door frame to conceal the seam between the door frame and the wall edges.
Came/Caming: A metal strip typically made of Brass or Zinc, which is used to hold pieces of glass in place. Used for more decorative designs.
Casing: A decorative moulding used to trim the inside edge of a door frame to conceal the seam between the door frame and the wall edges.
Core: The inside or middle of a door; it is also, the part of a door between jambs.
Deadbolt: A security lock that requires a key to open from the exterior side of the door.
Distressing wood: Coloring the surface of wood to give it an antique, worn appearance.
Door Lite: A glass pane in a door.
Door Slab: The actual section of a door which fits into the frame, made with wood or laminate.
Door Stop: The part of the frame upon which the door panel rests when closed.
Door Unit: An entire door, including frame jambs, hinges, etc.
Double Acting Door: A door that can be opened from either side, pushing or pulling. It is sometimes called a double-sided door or a Dutch door.
Draught: The gap at floor level.
Dutch Door: A door, usually exterior, with an upper and lower section that can be opened separately.
Finger Joint: A way of joining short sections of board stock together, end to end to make longer stock. Door and frame parts are often made using finger-jointed pine stock.
Fire Door: A door that complies with fire regulations.
French Door: A door with glass panes extending throughout its length with two parts that open outwards.
Fly Edge: The edges of the frame, thinner than the stiles and rails. It is the opposite of the reveal.
Flush Bolt: A bolt that is flush with the face or edge of the door when retracted.
Inactive Door: The door within a pair of doors in which the strike is fastened to receive the latch of the active door. The inactive door is hinged and can be operable when releasing the flush bolts that holds it in place.
Jamb: The top and two side posts of a doorway.
Latch: The locking device that is used to keep a door closed. The latch can be on the inside of the door, as in a bathroom, or on the outside of the door.
Left or Right hand: This refers to whether the door opens to the left or right.
Lock Rail: An intermediate horizontal member of a door, between the vertical stiles, at the height of the lock.
Lockset: The complete handle set within a locking system.
Mortise and Tenon Joint: A type of joint where the end of one of the members is inserted into a hole cut in the other member. The end of the first member is called the Tenon, and it is usually narrowed with respect to the rest of the piece. The hole in the second member is called the Mortise. The joint may be glued, pinned, or wedged to lock it in place.
Mull Cover: A mould which covers the mull post.
Mull Post: The vertical post in a door frame.
Mullion: A piece of hardware made of wood which divides the opening of a pair of doors.
Multi-Point Locking System: A locking system used to secure high-risk areas, such as detention centers.
Muntin: A short vertical or horizontal bar used to separate panes of glass in a window or panels in a door. The muntin extends from a stile, rail, or bar to another bar.
Ogee Moulding: A type of moulding used to decorate the edge of a door, seen most often in Victorian-style homes.
Panel: The area on a stile and rail door that is surrounded by the stiles and rails. (Ex. 6 panel door)
Pilaster: An attached column or post, often ornamental.
Pencil Post: A post that is attached to the middle of the face of a door and can be used to strengthen the door.
Plank: A simple wooden board consisting of little more than a sill and jamb
Pre-Hung: Doors put together with jambs, hinges and threshold to make a total working door system (a unit).
Prefinished Door: A ready to hang, pre-cut wooden door
Quarter Round: A moulding that covers the space between the face of a door and the floor
Rabbet: A cut along the jambs into which the door fits. Rough Opening: Dimensions of the opening in the framework of the home required to install a complete door unit. (Allowing1/2" clearance on top and each side for stabilization shims)
Rail: A horizontal bar of wood that connects the vertical bars, or stiles, in a door.
Raised Panel: A door panel on which the edges have been contoured or shaped to provide an aesthetically appealing, three-dimensional effect.
Recess: A space in a wall into which another part (a door or window) can be fitted. It is also a channel or groove in a piece of wood that is used to receive another piece.
Return: The edge of a door that returns to meet the wall. Returns are usually made of a different wood to the rest of the door.
Reveal: The gap between the edge of a door and the surrounding wall
Rough Opening: An unfinished opening where a window or door will be installed. Usage: Rough openings are lined by wood members; the top one is the "header" and the side ones are the "trimmers."
Sidelites: Are the side panels beside a door, typically filled with glass.
Sill: A horizontal beam below the door that supports the frame.
Simulated Divided Lite (SDL): A door that contains one single glass pane with interlocking muntin bars that lock into place, separating the glass into multiple door lites.
Slab: Just the door only, no frames, jambs, or parts added to make the door operate.
Stiles: The two outer vertical wood pieces of a door panel. The inner stile (i.e., the stile nearest the axis on which the door swings) is called the Hinge Stile; the outer stile is called the Lock Stile.
Strike: To lock into place by fitting in a jamb
Strike Plate: A metal plate or box which is set in a door jamb and is either pierced or recessed to receive the bolt or latch of a lock.
Tempered Glass: A glass that has been processed by controlled thermal or chemical treatments to increase its strength compared with normal glass. Tempered glass is made by processes which create balanced internal stresses which strengthen the glass. It will usually shatter into small fragments rather than sharp shards when broken, reducing the likelihood of severe injury and deep lacerations.
Threshold (Sill): The part of the door unit which is attached to the floor under the door.
Top Rail: The top horizontal moulding/strip of a door frame.
Transom: A decorative window directly above a door.
Trim: A strip placed over the face of a door jamb for decorative purposes.
True Divided Lite (TDL): Doors that contain individual panes of glass and are assembled using muntins.
Uneven-width hinges: These are hinges that have different sized leaves. The majority of household hinges are even-width, but uneven-width hinges can make a door more secure.
Weather-stripping: The process of sealing openings such as doors, windows, and trunks from the elements. The goal of weather-stripping is to prevent rain and water from entering by either blocking it out right or by blocking most of it and returning or rerouting it. A secondary goal of weather-stripping is to keep interior air in, thus saving energy with heating and air conditioning.
Note: This door terminology guide last updated 2023