accelerator vs auto

accelerator and auto both are nouns.

Word	Noun	Adjective	Verb	Adverb
accelerator	Yes	No	No	No
auto	Yes	No	No	No

accelerator (noun)	auto (noun)
a valve that regulates the supply of fuel to the engine	a motor vehicle with four wheels; usually propelled by an internal combustion engine
a scientific instrument that increases the kinetic energy of charged particles
a pedal that controls the throttle valve
(chemistry) a substance that initiates or accelerates a chemical reaction without itself being affected