any of a phylum (Cnidaria) of invertebrate animals, mainly marine, including jellyfishes, hydrozoans, and anthozoans, characterized by stinging cells and a saclike body cavity with a single opening for ingesting food and eliminating wastes; coelenterate
Origin: Modern Latin Cnidaria ; from Classical Greek knidē, nettle plush -aria: so called for the creatures' stinging cells
cnidarian definition by American Heritage Dictionary
Any of various invertebrate animals of the phylum Cnidaria, characterized by a radially symmetrical body with a saclike internal cavity, and including the jellyfishes, hydras, sea anemones, and corals. Also called coelenterate.
Of, relating to, or belonging to the phylum Cnidaria.
Origin: New Latin Cnīdāria, phylum name, from Greek knīdē, sea nettle.
Any of various invertebrate animals of the phylum Cnidaria (or Coelenterata), having a body with radial symmetry and tentacles that bear microscopic stinging capsules called nematocysts. The tentacles surround a mouth that opens into a saclike internal cavity and that is used both for ingesting food and for eliminating wastes. Cnidarians evolved in the Precambrian Era, but it is not known from what type of organism. Cnidarians include the jellyfishes, hydras, sea anemones, and corals. Also called coelenterate.