Dope, Pipe 
Lubricant compound used on seal pipe threads prior to making a threaded pipe connection. 

Doric 
The oldest and simples of the five classic architectural orders, originating in the Dorian region of ancient Greece. Ionic, Corinthian, Tuscan and Composite are the other four. 

Dormer 
Roofed projection built out from a sloping roof into which a window is set to provide additional interior light and ventilation. The word dormer comes from the word dormitory, which was normally in an attic area. 

Dormer Horizontal Cornice 
Horizontal exterior trim on a dormer. 

Dormer Rafter 
Roof rafters, which frame the dormer roof. 

Dormer Rake Cornice 
Exterior trim, which is located on the roof slope edge of a dormer. 

Dormer Window 
Window, which is installed in the wall of a dormer. 

Dormitory 
Sleeping facility for a large number of people, commonly used in colleges. 

Dosimeter 
Small device, which is used to measure the number of roentgens absorbed in a single exposure to radiation. 

Double Acting 
Moving or performing in two different directions. 

Double-acting Hinge
Door hinge that allows a door to swing both inward and outward. 

Double-alternate Saw Tooth Set 
Fine-toothed hacksaw blade whose blade has the teeth set, alternately, to the right and then the left. 

Double Brick 
Masonry brick with measurements of 4 x 5 1/3 x 8 inches. 

Double Coursing 
Installing siding shingles in double layers. 

Double-cut File 
File that has two sets of teeth cut in rows diagonally crossing each other. 

Double Declining Balance Depreciation Method 
Accelerated method in which a fixed percentage factor of two times the straight-line rate is multiplied each year by the declining balance of the fixed asset's book value. To compute the annual depreciation expense, the asset's book value at the beginning of the period is multiplied by the double declining rate. Although salvage value is not included in the initial calculation for depreciation, a fixed asset cannot be depreciated in the last year below its salvage value. 

Double-digit Inflation 
Annual rate of inflation of 10% or higher. 

Double Floor 
A floor where the binding joists support the common joists above and the ceiling below. 

Double Framing 
Construction method of using twice the number of framing members to provide additional structural strength. 

Double Glazing 
Double pane window with air space between the panes to provide additional insulation. 

Double-hung Window 
Window consisting of two sashes that slide up and down, with each sash closing a different part of the window, for example by sliding the upper or lower cash into position with the other, the window can be opened at the top or the bottom. 

Double Insulated 
Electrical power tools with parts that carry current being insulated from the person using it by internal insulation in addition to a non-conducting outer casing. 

Double Nailing 
Method of nailing where pairs of nails are driven in very close together; often used with wallboard. 

Double Pitch 
Roof design having two different pitches such as a gambrel roof. 

Double 
Plating Installation of a second structural member on top of the first, to strengthen walls. 

Double-pole, Double-throw Switch (DPDT) 
Switch which is able to connect or interrupt two electrical conductors simultaneously. 

Double-pole Reversing Switch 
Switching device that uses three switches to permit an outlet to be operated from all three switches. Also called a four-way switch, this electrical switch is used in conjunction with two three-way switches in cases where three points for controlling an electrical circuit are needed. 

Double-pole, Single-throw Switch (DPST) 
Electrical switch that connects or disconnects two pairs of terminals. 

Double Wall 
Wall, whose purpose is basically to isolate sound, is constructed by using a common plate wider than the two rows of offset studs, which are studs that are in a staggered or zigzag pattern, so that each side of the wall is attached to a different set of studs. Since the wallboard walls are not sharing common framing, sound is not directly transmitted from one wall to another. The insulation in the wall cavity, also serves to mute any noise. This type of wall is also referred to as double-stud wall, or offset-stud framing. 

Double-stud Wall 
Wall, whose purpose is basically to isolate sound, is constructed by using a common plate wider than the two rows of offset studs, which are studs that are in a staggered or zigzag pattern, so that each side of the wall is attached to a different set of studs. Since the wallboard walls are not sharing common framing, sound is not directly transmitted from one wall to another. The insulation in the wall cavity, also serves to mute any noise. This type of wall is also referred to as double wall, or offset-stud framing. 

Double-wall Siding
Siding in which sheathing is installed and is then covered by exterior siding. 

Double-welded Joint 
Joint welded from both sides. 

Double Y-branch 
Y-shaped plumbing fitting with two branches, each at an angle to the main run. 

Doubling Up 
Two families living in a residence designed for only one family, which violates single-family residence zoning. 

Douglas Fir 
This decay-resistant wood with good bending strength is the most common type of wood used in the making of plywood due the fact that it is hard and stiff with good ability to hold nails. 

Dovetail 
Woodworking joint whose ends are fanned out like a Dove's tail due to the recessed lots cut into the board, which are called mortises and the projection that fit into the mortises, which are called tenons. 

Dovetail Jig 
Device, which is also called a dovetail gauge, that hold the board ends that are being joined in a dovetail joint, so that the mortises and tenons are in the correct locations when cut with the proper router bit. 

Dovetail Joints 
Joints locking together two pieces of wood using meshed teeth shaped projects and cuts called mortises and tenons. 

Dovetail Saw 
Type of small, handheld backsaw which is used for cutting dovetails, it has a stiff blade and reinforced spine. 

Dowel 
1. Short, rounded, flat ended wooden stick, which fastens two members together by fitting into matching holes, which are drilled into each member. 
2. Straight, metal bars which are used to connect masonry. 

Dowel Center 
Plug, which marks the position where pieces have to be cut to be joined together evenly. One end is set into an already drilled dowel hole on a board and then the other piece of board to be joined is butted up against the other end of the plug, which marks the position where the hole should go. 

Dowel Gauge 
Device, which is also called a dovetail jig, that hold the board ends that are being joined in a dovetail joint, so that the mortises and tenons are in the correct locations when cut with the proper router bit. 

Dowel Joint 
Joint held together by the short, rounded, and flat ended wooden sticks called dowels. 

Dower 
The legal right of a widow to a portion of her deceased husband's real estate. 

Down Payment 
The difference between the financed portion of the purchase price and the purchase price. This is normally paid by the purchaser. 

Down Zoning 
Rezoning of land from a higher density use to a lower density use. 

Downdraft 
Downward current of air. 

Downdrain
Drain that is intended to direct water runoff away from roads. 

Downhand Welding 
Weld, also called a flat position weld, made on the upper, horizontal surface of the work, which has been laid flat or almost flat. 

Downspout 
The pipe or duct used to carry rainwater from a gutter to the ground. Also called a leader, this vertical portion of the gutter system, carries water away from the house, stopping water from causing basement leaks. 

Downstream 
Water flowing in the direction of the current. 

Downtime
Lost time when repairs are needed on a job in progress. 

Dozer 
Slang for the piece of heavy construction equipment, called a bulldozer. The machine consists of tractor-like machinery, which moves on treads and has an adjustable, front-mounted scraper blade which moves the dirt by pushing it in front of the machine and is used to smooth and level a building site. 

Dozing 
Slang for the movement of material by use of a bulldozer or dozer.