1 : any of numerous relatively small elongated soft-bodied animals especially of the phyla Annelida and Chaetognatha and Nematoda and Nemertea and Platyhelminthes; also many insect larvae
2 : a soft thick wormlike larva of certain beetles and other insects
3 : worm that is parasitic on the intestines of vertebrates especially roundworms and tapeworms and flukes
