nematode /nem″ətōd/ [Gk, nema + eidos, form] , a multicellular, parasitic animal of the phylum Nematoda. All roundworms belong to the phylum, including Ancylostoma duodenale, Ascaris lumbricoides, Enterobius vermicularis, Necator americanus, Strongyloides stercoralis, and several other species.
