basalt vs volcanic rock

basalt and volcanic rock both are nouns.

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

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

basalt: the commonest type of solidified lava; a dense dark grey fine-grained igneous rock that is composed chiefly of plagioclase feldspar and pyroxene
volcanic rock: extrusive igneous rock solidified near or on the surface of the Earth

basalt (noun)	volcanic rock (noun)
the commonest type of solidified lava; a dense dark grey fine-grained igneous rock that is composed chiefly of plagioclase feldspar and pyroxene	extrusive igneous rock solidified near or on the surface of the Earth