nematoda

a class of worms, Modern Latin compound of nemat- “thread” (from Greek nema, genitive nematos “thread,” from stem of nein “to spin;” see needle (n.)) + -odes “like, of the nature of” (see -oid). n.

1. A phylum of worms including species parasitic in humans and plants as well as free-living nonparasitic species in soil or water. It includes the intestinal roundworms and filarial roundworms.