- Anything that increases rapidity of action or function.
- In physiology, a nerve, muscle, or substance that quickens movement or response.
- A catalytic agent used to hasten a chemical reaction.
- In nuclear physics, a device that accelerates charged particles (protons) to high speed to produce nuclear reactions in a target, for the study of subatomic structure, for the production of radionuclides, or for radiation therapy.
[L. accelerans, pres. p. of ac-celero, to hasten, fr. celer, swift]