volcano vs mountain

volcano and mountain both are nouns.

Word	Noun	Adjective	Verb	Adverb
volcano	Yes	No	No	No
mountain	Yes	No	No	No

As nouns, mountain is a hypernym of volcano; that is, mountain is a word with a broader meaning than volcano:

volcano: a mountain formed by volcanic material
mountain: a land mass that projects well above its surroundings; higher than a hill

Other hypernyms of volcano include mount.

volcano (noun)	mountain (noun)
a mountain formed by volcanic material	a land mass that projects well above its surroundings; higher than a hill
a fissure in the earth's crust (or in the surface of some other planet) through which molten lava and gases erupt	(often followed by `of') a large number or amount or extent