accelerator

noun

1. a person or thing that accelerates.
2. Automotive. a device, usually operated by the foot, for controlling the speed of an engine.
3. British. any two- or three-wheeled motor vehicle, as a motorcycle or motor scooter.
4. Photography. a chemical, usually an alkali, added to a developer to increase the rate of development.
5. 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.
6. Anatomy, Physiology. any muscle, nerve, or activating substance that quickens a movement.
7. 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.
8. Economics. acceleration coefficient.

noun

1. a device for increasing speed, esp a pedal for controlling the fuel intake in a motor vehicle; throttle
2. Also called (not in technical usage): atom smasher physics a machine for increasing the kinetic energy of subatomic particles or atomic nuclei and focusing them on a target
3. 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
4. economics (in an economy) the relationship between the rate of change in output or sales and the consequent change in the level of investment
5. anatomy a muscle or nerve that increases the rate of a function

n.

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

n.

1. One that increases rapidity of action or function.
2. A nerve, muscle, or substance that quickens movement or response.
3. A catalyst.