tuff vs volcanic rock

tuff and volcanic rock both are nouns.

Word	Noun	Adjective	Verb	Adverb
tuff	Yes	No	No	No
volcanic rock	Yes	No	No	No

As nouns, volcanic rock is a hypernym of tuff; that is, volcanic rock is a word with a broader meaning than tuff:

tuff: hard volcanic rock composed of compacted volcanic ash
volcanic rock: extrusive igneous rock solidified near or on the surface of the Earth

tuff (noun)	volcanic rock (noun)
hard volcanic rock composed of compacted volcanic ash	extrusive igneous rock solidified near or on the surface of the Earth