DuckCorp Dico

Found one definition

1.                 From The Collaborative International Dictionary of English v.0.48:
                   
   
   
                   
                     
   Prion \Pri"on\ (pr[=e]"[o^]n), n.
      any of several types of protein particle lacking nucleic
      acid, believed to be the cause of certain slow-developing
      infectious diseases such as scapie in sheep, and
      Creutzfeldt-Jakob disease and Kuru in humans. [informal]
      [PJC]