Any microscopic worm of the rhombozoan group Dicyemida, having a complicated life cycle with two kinds of larvae.
The Dicyemida have been treated as an order of the phylum Mesozoa or of the phylum Rhombozoa. The name is now frequently regarded as a preferred synonym of the phylum Rhombozoa.
Late 19th century. From scientific Latin Dicyema, genus name + -id.