Medical Definition of Nemathelminthes
in some classifications : a phylum including the nematodes and horsehair worms and sometimes the acanthocephalans, rotifers, gastrotrichs, and minute marine organisms of a related class (Kinorhyncha) which are all more or less wormlike animals with a cylindrical unsegmented body covered by an ectoderm without cilia that secretes an external cuticle
Seen and Heard
What made you want to look up Nemathelminthes? Please tell us where you read or heard it (including the quote, if possible).