/ak sel"euh ray'teuhr/ , n.
1. a person or thing that accelerates.
2. Auto. a device, usually operated by the foot, for controlling the speed of an engine.
3. Brit. any two- or three-wheeled motor vehicle, as a motorcycle or motor scooter.
4. Photog. a chemical, usually an alkali, added to a developer to increase the rate of development.
5. Also called accelerant . Chem. 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. Anat. , Physiol. 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. Econ. See acceleration coefficient .
[ 1605-15; 1930-35 for def. 7; ACCELERATE + -OR 2 ]