cholesterol vs sterol

cholesterol and sterol both are nouns.

Word	Noun	Adjective	Verb	Adverb
cholesterol	Yes	No	No	No
sterol	Yes	No	No	No

As nouns, sterol is a hypernym of cholesterol; that is, sterol is a word with a broader meaning than cholesterol:

cholesterol: an animal sterol that is normally synthesized by the liver; the most abundant steroid in animal tissues
sterol: any of a group of natural steroid alcohols derived from plants or animals; they are waxy insoluble substances

Other hypernyms of cholesterol include steroid alcohol.

cholesterol (noun)	sterol (noun)
an animal sterol that is normally synthesized by the liver; the most abundant steroid in animal tissues	any of a group of natural steroid alcohols derived from plants or animals; they are waxy insoluble substances