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-cut file
File that has two sets of teeth cut in rows diagonally crossing each other.
Double-digit inflation
Annual rate of inflation of 10% or higher.
Double-fired tiles
Glazed tiles produced by an initial firing of the shaped tile body and then a second firing once the glaze or decoration has been applied.
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-pane or glazed window
A type of window having two layers (panes or glazing) of glass separated by an air space. Each layer of glass and surrounding air space reradiates and traps some of the heat that passes through thereby increasing the windows resistance to heat loss (R-value).
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, double-throw switch (dpdt)
Switch which is able to connect or interrupt two electrical conductors simultaneously.
Double-pole, single-throw switch (dpst)
Electrical switch that connects or disconnects two pairs of terminals.
