Learn That Word

Synonyms for Accelerator (same or very similar meaning)

WordNet sense 1 ((chemistry) a substance that initiates or accelerates a chemical reaction without itself being affected):

WordNet sense 2 (a pedal that controls the throttle valve):
gas, gun, throttle, accelerator pedal, gas pedal

WordNet sense 3 (a scientific instrument that increases the kinetic energy of charged particles):
atom smasher, particle accelerator

WordNet sense 4 (a valve that regulates the supply of fuel to the engine):
throttle valve

From the ODE community, based on WordNetadd/edit