nemertean vs ribbon worm

nemertean and ribbon worm both are nouns.

Word	Noun	Adjective	Verb	Adverb
nemertean	Yes	No	No	No
ribbon worm	Yes	No	No	No

As nouns, nemertean and ribbon worm are synonyms defined as:

nemertean and ribbon worm: soft unsegmented marine worms that have a threadlike proboscis and the ability to stretch and contract

Other synonyms of nemertean include nemertine, proboscis worm.

nemertean (noun)	ribbon worm (noun)
soft unsegmented marine worms that have a threadlike proboscis and the ability to stretch and contract	soft unsegmented marine worms that have a threadlike proboscis and the ability to stretch and contract