Siding boards with a tapered cross-section, of which, the top edge is narrower. Installed horizontally, the top edge fits into a groove in the bottom edge of the board above it.
Dropped ceiling
Flat ceiling, which is built lower than the original ceiling.
Dropping a hip rafter
To prevent the upper edges of a hip rafter from projecting over the plane of the adjoining roof, a deep seat cut is made so that the hip rafter sits lower than the surrounding roof framing.
Drum
(1) Any of various drum-like cylindrical objects or containers. (2) Rotating, power-driven cylinder used as a hoist by wrapping a hoisting rope, which is attached by a pulley or pulleys, to the load being hoisted.
Drum sander
Rubber drum, mounted on an arbor, which is held in the chuck of a motor that turns, thereby rubbing its cover of abrasive material, against the work that is held against it for sanding.
Drum trap
Plumbing fixture, which is cylindrical in shape, which retains water as a seal, with an outlet at its top and an inlet at its base. Used in plumbing fixtures that are too low to the floor for installation of a P-trap.
Drupe
A type of fruit (i.e. plums and cherries). The fruit wall is fleshy. The outside layer is generally juicy.
Dry battery
Sealed electrical storage battery that contains no free liquid.
Dry bulb
Thermometer Instrument which measure the amount of heat in the air by the expansion f a liquid in a graduated glass tube with a reservoir bulb at one end. Alternately, by use of a bimetallic strip which moves the indicator on a scale when heat causes the two metals to expand at different rates. Normally used for outdoor temperatures.
Dry bulb temperature
The temperature of air in degrees Fahrenheit measured by an ordinary thermometer.
