noun (plural aschelminths or aschelminthes)Zoology
- an invertebrate animal belonging to a group of phyla that are distinguished by the lack of a well-developed coelom and blood vessels. Most are minute worm-like animals, including the nematodes, rotifers, and water bears.
- Phylum Nematoda and about seven minor phyla, formerly placed in a phylum Aschelminthes
from modern Latin Aschelminthes (former phylum name), from Greek askos 'sac' + helminth 'worm' (from the former belief that animals of this group had a fluid-filled internal sac)