groundmass vs igneous rock

groundmass and igneous rock both are nouns.

Word	Noun	Adjective	Verb	Adverb
groundmass	Yes	No	No	No
igneous rock	Yes	No	No	No

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

groundmass: (geology) the matrix of fine-grained crystalline material in which larger crystals are embedded
igneous rock: rock formed by the solidification of molten magma

groundmass (noun)	igneous rock (noun)
(geology) the matrix of fine-grained crystalline material in which larger crystals are embedded	rock formed by the solidification of molten magma