ribbon worm vs nemertean

ribbon worm and nemertean both are nouns.

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

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

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

Other synonyms of ribbon worm include nemertine, proboscis worm.

ribbon worm (noun)	nemertean (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