treadle vs lever

treadle and lever both are nouns.

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

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

treadle (noun)	lever (noun)
a lever that is operated with the foot	a rigid bar pivoted about a fulcrum
	a flat metal tumbler in a lever lock
	a simple machine that gives a mechanical advantage when given a fulcrum

treadle (verb)	lever (verb)
operate (machinery) by a treadle	to move or force, especially in an effort to get something open
tread over