univalve vs gastropod

univalve and gastropod both are nouns.

Word	Noun	Adjective	Verb	Adverb
univalve	Yes	Yes	No	No
gastropod	Yes	No	No	No

As nouns, univalve and gastropod are synonyms defined as:

univalve and gastropod: a class of mollusks typically having a one-piece coiled shell and flattened muscular foot with a head bearing stalked eyes

univalve (noun)	gastropod (noun)
a class of mollusks typically having a one-piece coiled shell and flattened muscular foot with a head bearing stalked eyes	a class of mollusks typically having a one-piece coiled shell and flattened muscular foot with a head bearing stalked eyes

univalve (adjective)	gastropod (adjective)
used of mollusks, especially gastropods, as snails etc.