Door Terminology
The ins and outs of door technology may be old or very new.
• ASTRAGAL A moulding applied to one stile of a French door, sliding French door, or French casement window, which the other door panel or window sash strikes.
• BATTEN DOOR A wood door made of vertical planks or boards fastened together with horizontal boards (battens), which are usually nailed to the inside of the door.
• COPE-AND-STICK A frame-and-panel joinery technique often used in making doors, where a mating member on the frame is given a decorative profile on the edge that joins to a panel.
• DIVIDED LIGHTS Glass panes (lights) held by permanent, stationary muntins and bars that separate individual panes in a window or door sash. Often sold in “lite” (grid) variations by door makers.
• DUTCH DOOR Introduced by Dutch colonists who settled in the Hudson River Valley in the early 1600s, these are usually wood batten doors separated into top and bottom halves. The top could be opened for light and air while the closed bottom kept livestock out.
• FRAME-AND-PANEL A style of construction that features vertical wood stiles and horizontal rails that form one or more frames around thinner recessed inner panels. Doors usually have between one and eight panels, and the door is often referred to by the number of panels it has.
• GLAZING Installing glass into windows and doors, or the glass itself. Single glazed means glazing with a single piece of glass; double or insulated glazing means two panes of glass separated by a spacer and hermetically sealed together with insulating dead air space or gas between the panes.
• MORTISE-AND TENON A joinery system by which a projecting tenon fits snugly into a mating mortise in either a stile or rail. Once the tenon is in place, it’s fastened by drilling a hole through both the mortise and tenon and driving a wood peg or other fastener into the hole.
• PASSAGE DOOR An interior door between a hall and a room, or between two rooms.
• RAIL A horizontal bar that connects the vertical bars, called stiles, in a door or window frame.
• STILE A vertical length of material (usually wood) in door or window frames, connected to other stiles by horizontal bars called rails.
• U FACTOR A measure of the ability to transfer heat in glass windows or doors. The lower the number, the more efficient the glazing.