accelerator vs treadle

accelerator and treadle both are nouns.

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

As nouns, treadle is a hypernym of accelerator; that is, treadle is a word with a broader meaning than accelerator:

Other hypernyms of accelerator include foot lever, foot pedal, pedal.

accelerator (noun)	treadle (noun)
a valve that regulates the supply of fuel to the engine	a lever that is operated with the foot
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

accelerator (verb)	treadle (verb)
	operate (machinery) by a treadle
	tread over