siphonophore vs hydrozoan

siphonophore and hydrozoan both are nouns.

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

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

siphonophore: a floating or swimming oceanic colony of polyps often transparent or showily colored
hydrozoan: colonial coelenterates having the polyp phase dominant

Other hypernyms of siphonophore include hydroid.

siphonophore (noun)	hydrozoan (noun)
a floating or swimming oceanic colony of polyps often transparent or showily colored	colonial coelenterates having the polyp phase dominant