• (n.) One of the peculiar stinging, cells found in Coelenterata; a nematocyst; a lasso cell.
Synonym: nematocyst. ... Origin: G. Knide, nettle ... (05 Mar 2000) ... 
Cni'da (nī'dȧ) noun ; plural Cnidæ (nī'dē). [ New Latin , from Greek 
Type: Term Pronunciation: nī′dă, nī′dē Synonyms: nematocyst
cnida One of the peculiar stinging, cells found in Coelenterata (one of the major phyla of invertebrates, to which such forms as jellyfish belong); a nematocyst; a lasso cell. A nematocyst is a stinging mechanism used for defense and to capture prey, by Hydra and other members of the Cnidaria (Coelenterata). It is located within a specialized cell...
a nematocyst.