Also found in: Dictionary, Thesaurus, Medical, Wikipedia.
1. any invertebrate of the phylum Cnidaria (formerly Coelenterata), having a saclike body with a single opening (mouth), which occurs in polyp and medusa forms. Coelenterates include the hydra, jellyfishes, sea anemones, and corals
2. (loosely) any invertebrate of the phyla Cnidaria or Ctenophora
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005