sertularian vs hydrozoan

sertularian and hydrozoan both are nouns.

Word	Noun	Adjective	Verb	Adverb
sertularian	Yes	No	No	No
hydrozoan	Yes	No	No	No

As nouns, hydrozoan is a hypernym of sertularian; that is, hydrozoan is a word with a broader meaning than sertularian:

sertularian: feathery colony of long-branched stems bearing stalkless paired polyps
hydrozoan: colonial coelenterates having the polyp phase dominant

Other hypernyms of sertularian include hydroid.

sertularian (noun)	hydrozoan (noun)
feathery colony of long-branched stems bearing stalkless paired polyps	colonial coelenterates having the polyp phase dominant