WordWeb Online

1. A pedal that controls the throttle valve
   "he stepped on the accelerator";
   - accelerator pedal, gas pedal [N. Amer], gas [N. Amer], throttle
    
2. A valve that regulates the supply of fuel to the engine
   - throttle, throttle valve
    
3. (chemistry) a substance that initiates or accelerates a chemical reaction without itself being affected
   - catalyst
    
4. A scientific instrument that increases the kinetic energy of charged particles
   - particle accelerator, atom smasher

Derived forms: accelerators

Type of: activator, foot lever, foot pedal, pedal, scientific instrument, treadle, valve

Antonym: anticatalyst

Part of: aeroplane [Brit], airplane [N. Amer], auto [informal], autocar [archaic], automobile [N. Amer], car, fuel system, motorcar, plane, wheel [informal], whip [US, informal]

Encyclopedia: Accelerator