subphylum Craniata vs bird genus

subphylum Craniata and bird genus both are nouns.

Word	Noun	Adjective	Verb	Adverb
subphylum Craniata	Yes	No	No	No
bird genus	Yes	No	No	No

subphylum Craniata (noun)	bird genus (noun)
fishes, amphibians, reptiles, birds, mammals	a genus of birds