Do
- Do Loop
- A programming language statement which allows code to be repeatedly executed.
- Dobson Unit
- Unit used in geophysics to measure the ozone in the atmosphere.
- Dodecagon
- A polygon with 12 sides.
- Dodecahedron
- A solid figure with 12 faces.
- Dodecane
C12H26
A thick, oily liquid of the paraffin series. It is used as a solvent, distillation chaser and is also the average component of diesel fuel.
- Dolby Prologic
- This is a four-channel sound reproduction system consisting of left, center, right and rear channel, (the single rear channel is usually played through two speakers).
- Dolby, Ray
- Audio system innovator and founder of Dolby Laboratories.
- Domain
- The set of all allowable inputs for a function.
- Domain Name
- The unique name that identifies an Internet site.
- Domain Naming System
- A system used by the Internet for translating names of host computers into addresses.
- Domain of the Function
- The set of numbers x for which f(x) is defined.
- Dome
- A roof formed by a series of arches, roughly forming a semicircle.
- Domino
- Two congruent squares joined along an edge.
- Domoic Acid
C15H21NO6
Domoic acid is a toxic amino acid produced by certain species of algae.
- Donjon
- The principal tower of a castle.
- Donor
- An atom which is likely to give off one or more electrons when placed in a crystal.
- Door
- Opening to a room, compartment or system.
- Doping
- The intentional alloying of semiconductor materials with controlled concentrations of donor or acceptor impurities
- Doppler Effect
- A change in the frequency of a periodic wave due to the motion of the observer, the source, or both.
- Doppler Sonar
- An acoustic instrument that measures the change in the acoustic frequency of the scattered sound or echo from that of the transmitted pulse. The magnitude and direction of the shift in frequency is related to the relative motion of the sensor and the scatterer.
- Doric Order
- The first and simplest of the three Greek orders and the only one that normally has no base.
- Dormant Volcano
- The term is used to describe a volcano which is presently inactive but which may erupt again.
- Dormer Window
- A window housed in a gable or similar structure affixed to the sloping part of a roof, providing natural light and ventilation to the rooms beneath the roof.
- DOS
- Abbreviation of Disk Operating System.
- Dosimeter
- A device worn by a worker for determining the worker's accumulated noise exposure with regard to level and time according to a pre-determined integration formula.
- Dot
- A description of a point in which the point has a definite size.
- Dot Product
- The dot product of two vectors is obtained by adding the products of the respective components of the vectors.
- Dots Per Inch
- A unit used to measure the resolution, or sharpness of an image.
- Double Acoustic Barrier
- An acoustic barrier consisting of two panels with a gap between.
- Double Blind Experiment
- Neither the subjects nor the people evaluating the subjects knows who is in the treatment group and who is in the control group.
- Double Bond
- When an atom is bonded to another atom by two sets of electron pairs.
- Double Data Rate
- A fast type of RAM for a PC, originally only used on high performance graphics cards but now being used for general memory in most high-end PCs.
- Double Displacement
- A reaction in which two reactants trade fragments.
- Double Glazing
- Two layers of glazing used to improve thermal and acoustic radiation.
- Double Helical Gear
- The double helical gear gives a much smoother still operation than the spur or helical gear and reduces the noise levels further.
- Double Helix
- The natural coiled conformation of two complementary, antiparallel DNA chains by the formation of A-T and G-C base pairs.
- Double Hung Window
- Two sashes which, when both are closed, are positioned one immediately above the other.
- Double Row Bearing
- A bearing having two rows of rolling elements.
- Double Word
- Unit of information equal to 2 short words, 4 bytes or 32 bits.
- Double-Ended Spanner
- A tool which has a hexagon ring at each end.
- Dovetail Joint
- A joint where the fingers are shaped like a doves tail, used to join pieces at 90 degrees.
- Dovetail Saw
- A saw designed for cutting dovetail joints and other wood joints.
- Dowel
- A pin fitted or keyed in two adjacent parts to accurately align the parts when assembling them.
- Down Feed
- A seldom used method of feeding work into milling cutters.
- Down Quark
- The second flavour of quark (in order of increasing mass), with electric charge -1/3.
- Downcomer
- Large external pipes in many water-tube boilers, carrying unheated cold water from the steam drum down to the water drum as part of the circulation path.
- Downconverter
- A device which provides frequency conversion to a lower frequency.
- Downforce
- The opposite of aerodynamic lift, sometimes referred to as negative lift. The force caused by the air over the wings to push the car into the ground, increasing grip and cornering speeds.
- Downsampling
- Downsampling is used to reduce the sampling rate of data.
- Downspout
- The vertical part of a drainage system from a roof-which forms a channel or pipe to remove water from the gutters.
- Downstream Face
- The side of the dam that is not against the water.
- Downturned Eye
- Refers to the eye of a leaf spring when the spring turns down to form the eye.
- Dozen
- Twelve pieces of something.