- an organ in coelenterates consisting of a minute capsule containing an ejectable thread that causes a sting.
- a structure in coelenterates, such as jellyfish, consisting of a capsule containing a hollow coiled thread that can be everted to sting or paralyse prey and enemies
n.1875, from nemato-, comb. form of Greek nema, nematos “thread” (genitive nematos), from stem of nein “to spin” (see needle (n.)) + cyst. n.
- A capsule within specialized cells of certain coelenterates containing a barbed, threadlike tube that delivers a paralyzing sting.
- One of the minute capsules in the tentacles of cnidarians, such as jellyfish, hydras, or sea anemones, used for stinging. The capsule is produced by a special cell (called a cnidoblast) and contains a tightly coiled barbed thread that quickly shoots forth if the capsule’s lid is disturbed. The thread often contains poison.