1. (

• accelerator ,
• accelerator_pedal ,
• gas_pedal ,
• gas ,
• throttle ,
• gun ,

) a pedal that controls the throttle valve; "he stepped on the gas" ;

2. (

• accelerator ,
• throttle ,
• throttle_valve

) a valve that regulates the supply of fuel to the engine ;

3. (

• catalyst ,
• accelerator

) (chemistry) a substance that initiates or accelerates a chemical reaction without itself being affected ;

4. (

• accelerator ,
• particle_accelerator ,
• atom_smasher

) a scientific instrument that increases the kinetic energy of charged particles ;