neritid vs neritid gastropod

neritid and neritid gastropod both are nouns.

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

As nouns, neritid and neritid gastropod are synonyms defined as:

neritid and neritid gastropod: operculate seasnail of coastal waters with a short spiral shell

neritid (noun)	neritid gastropod (noun)
operculate seasnail of coastal waters with a short spiral shell	operculate seasnail of coastal waters with a short spiral shell