phylum Cnidaria vs class Hydrozoa

phylum Cnidaria and class Hydrozoa both are nouns.

Word	Noun	Adjective	Verb	Adverb
phylum Cnidaria	Yes	No	No	No
class Hydrozoa	Yes	No	No	No

phylum Cnidaria (noun)	class Hydrozoa (noun)
hydras, polyps, jellyfishes, sea anemones, corals	coelenterates typically having alternation of generations; hydroid phase is usually colonial giving rise to the medusoid phase by budding: hydras and jellyfishes