cnidocyst
noun
cni·do·cyst ˈnī-də-ˌsist 
plural cnidocysts
: nematocyst
The stinging cells, or cnidocysts, of sea anemones, jellyfish and other cnidarians work like tiny harpoons when triggered by physical contact.
Colin Barras
Colin Barras
Word History
Etymology
borrowed from German Cnidocyste, from Greek knī́dē "nettle, sea nettle" + German -o- -o- + -cyste -cyst — more at cnidarian
First Known Use
1888, in the meaning defined above