Any of various parasitic and nonparasitic worms of the phylum Platyhelminthes, such as a tapeworm or a planarian, characteristically having a soft, flat, bilaterally symmetrical body and no body cavity.

• 扁虫扁形动物门的寄生或非寄生虫中的任一种，以具有柔软、扁平且两面对称的身体和无体腔为特征，如绦虫或涡虫