platyhelminth vs flatworm

platyhelminth and flatworm both are nouns.

Word	Noun	Adjective	Verb	Adverb
platyhelminth	Yes	No	No	No
flatworm	Yes	No	No	No

As nouns, platyhelminth and flatworm are synonyms defined as:

platyhelminth and flatworm: parasitic or free-living worms having a flattened body

platyhelminth (noun)	flatworm (noun)
parasitic or free-living worms having a flattened body	parasitic or free-living worms having a flattened body