a device for increasing speed, esp a pedal for controlling the fuel intake in a motor vehicle; throttle a machine for increasing the kinetic energy of subatomic particles or atomic nuclei and focusing them on a target 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
WordReference Random House Learner's Dictionary of American English © 2025
ac•cel•er•a•tor /ækˈsɛləˌreɪtɚ/USA pronunciation
n. [countable]
WordReference Random House Unabridged Dictionary of American English © 2025- Automotivea device, esp. a pedal, for controlling the speed of a motor vehicle engine.
ac•cel•er•a•tor
(ak sel′ə rā′tər),USA pronunciation n.
- a person or thing that accelerates.
- Automotivea device, usually operated by the foot, for controlling the speed of an engine.
- British Termsany two- or three-wheeled motor vehicle, as a motorcycle or motor scooter.
- Photographya chemical, usually an alkali, added to a developer to increase the rate of development.
- ChemistryAlso called accelerant. 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.
- Anatomyany muscle, nerve, or activating substance that quickens a movement.
- PhysicsAlso called atom smasher, particle accelerator. an electrostatic or electromagnetic device, as a cyclotron, that produces high-energy particles and focuses them on a target.
- Business[Econ.]See acceleration coefficient.
- 1605–15; 1930–35 for def. 7; accelerate + -or2
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