cro·tox·in (krō'tŏk'sĭn) n. A crystalline neurotoxin found in the venom of the rattlesnake, Crotalus terrificus.
[New Latin Crotalus, rattlesnake genus (from Latin crotalum, kind of rattle or castanet, from Greek krotalon, clapper, from krotein, to strike, beat) + toxin.]