pedal vs accelerator

pedal and accelerator both are nouns.

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

As nouns, accelerator is a hyponym of pedal; that is, accelerator is a word with a more specific, narrower meaning than pedal:

pedal (noun)	accelerator (noun)
a lever that is operated with the foot	a valve that regulates the supply of fuel to the engine
a sustained bass note	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

pedal (adjective)	accelerator (adjective)
of or relating to the feet

pedal (verb)	accelerator (verb)
operate the pedals on a keyboard instrument
ride a bicycle