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[ak-sel-uh-rey-ter] /ækˈsɛl əˌreɪ tər/
a person or thing that accelerates.
Automotive. a device, usually operated by the foot, for controlling the speed of an engine.
British. any two- or three-wheeled motor vehicle, as a motorcycle or motor scooter.
Photography. a chemical, usually an alkali, added to a developer to increase the rate of development.
Also called accelerant. Chemistry. any substance that increases the speed of a chemical change, as one that increases the rate of vulcanization of rubber or that hastens the setting of concrete, mortar, plaster, or the like.
Anatomy, Physiology. any muscle, nerve, or activating substance that quickens a movement.
Also called atom smasher, particle accelerator. Physics. an electrostatic or electromagnetic device, as a cyclotron, that produces high-energy particles and focuses them on a target.
Origin of accelerator
1605-15; 1930-35 for def 7; accelerate + -or2 Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the Web for accelerator
Historical Examples
  • Cloud eased up his accelerator, eased down his mighty brakes.

    The Vortex Blaster Edward Elmer Smith
  • "Say not so," says Barry, steppin' on the accelerator careless.

    Torchy and Vee Sewell Ford
  • The alkali sets the reducer in action and is called the accelerator.

  • She had taken her foot off the accelerator, and the car slowed down.

  • Then Eileen stepped on the accelerator, the car shot forward, and was almost instantly out of sight.

    The Dragon's Secret Augusta Huiell Seaman
  • Rick kept the accelerator to the floor except on the worst curves.

    The Golden Skull John Blaine
  • In tachycardia there is an irritation of the accelerator nerves to the heart, in brachycardia of the inhibitory nerves.

    Psychotherapy James J. Walsh
  • Scarcely had the beast come abreast of him than his foot leaped to the accelerator.

    The Mad King Edgar Rice Burroughs
  • The village passed, he jammed down the accelerator and once more the car sprang forward.

    The Man with the Clubfoot Valentine Williams
  • The roads were empty at that hour, and her foot pressed the accelerator.

    Manslaughter Alice Duer Miller
British Dictionary definitions for accelerator


a device for increasing speed, esp a pedal for controlling the fuel intake in a motor vehicle; throttle
(physics) Also called (not in technical usage) atom smasher. a machine for increasing the kinetic energy of subatomic particles or atomic nuclei and focusing them on a target
(chem) a substance that increases the speed of a chemical reaction, esp one that increases the rate of vulcanization of rubber, the rate of development in photography, the rate of setting of synthetic resins, or the rate of setting of concrete; catalyst
(economics) (in an economy) the relationship between the rate of change in output or sales and the consequent change in the level of investment
(anatomy) a muscle or nerve that increases the rate of a function
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for accelerator

1610s, from Latin accelerator, agent noun from accelerare (see accelerate). Motor vehicle sense is from 1900.

Online Etymology Dictionary, © 2010 Douglas Harper
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accelerator in Medicine

accelerator ac·cel·er·a·tor (āk-sěl'ə-rā'tər)

  1. One that increases rapidity of action or function.

  2. A nerve, muscle, or substance that quickens movement or response.

  3. A catalyst.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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accelerator in Technology
Additional hardware to perform some function faster than is possible in software running on the normal CPU. Examples include graphics accelerators and floating-point accelerators.
The Free On-line Dictionary of Computing, © Denis Howe 2010
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