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Definition of Ricin toxin
1. Noun. A toxic protein extracted from castor beans; used as a chemical reagent; can be used as a bioweapon. "One milligram of ricin can kill an adult" 
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1. Noun. A toxic protein extracted from castor beans; used as a chemical reagent; can be used as a bioweapon. "One milligram of ricin can kill an adult"