knoll vs hill

knoll and hill both are nouns.

Word	Noun	Adjective	Verb	Adverb
knoll	Yes	No	No	No
hill	Yes	No	Yes	No

As nouns, hill is a hypernym of knoll; that is, hill is a word with a broader meaning than knoll:

knoll (noun)	hill (noun)
a small natural hill	(baseball) the slight elevation on which the pitcher stands
	structure consisting of an artificial heap or bank usually of earth or stones
	a local and well-defined elevation of the land

knoll (verb)	hill (verb)
	form into a hill