phylum Arthropoda vs Hexapoda

phylum Arthropoda and Hexapoda both are nouns.

Word	Noun	Adjective	Verb	Adverb
phylum Arthropoda	Yes	No	No	No
Hexapoda	Yes	No	No	No

phylum Arthropoda (noun)	Hexapoda (noun)
jointed-foot invertebrates: arachnids, crustaceans, insects, millipedes, centipedes	insects; about five-sixths of all known animal species