1. Anything that increases rapidity of action or function. 2. In physiology, a nerve, muscle, or substance that quickens movement or response. 3. A catalytic agent used to hasten a chemical reaction. SYN: accelerant. 4. In nuclear physics, a device that accelerates charged particles ( e.g., protons) to high speed in order to produce nuclear reactions in a target, for the study of subatomic structure or for the production of radionuclides or for radiation therapy. [L. accelerans, pres. p. of ac-celero, to hasten, fr. celer, swift]
- linear a. (LINAC) a device imparting high velocity and energy to atomic and subatomic particles; an important device for radiation therapy.
- proserum prothrombin conversion a. (PPCA) obsolete term for factor VIII.
- prothrombin a. obsolete term for factor V.
- serum a. obsolete term for factor VII.
- serum prothrombin conversion a. (SPCA) obsolete term for factor VII.

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ac·cel·er·a·tor ik-'sel-ə-.rāt-ər, ak- n one that accelerates: as
a) a muscle or nerve that speeds the performance of an action <a cardiac \accelerator>
b) a substance that speeds a chemical reaction
c) an apparatus for imparting high velocities to charged particles (as electrons)

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ac·cel·er·a·tor (ak-selґər-a″tər) [L. “hastener”] 1. an agent or apparatus that is used to increase the rate at which an object proceeds or a substance acts or at which some reaction occurs. 2. any nerve or muscle which hastens the performance of a function. 3. any of a group of chemicals used in the vulcanization of rubber or other polymerization reactions; they frequently cause dermatitis in workers.

Medical dictionary. 2011.