Source : Webster's Revised Unabridged Dictionary (1913)

Wolfsbane \Wolfs"bane`\, n. (Bot.)
   A poisonous plant ({Aconitum Lycoctonum}), a kind of
   monkshood; also, by extension, any plant or species of the
   genus {Aconitum}. See {Aconite}.

Source : WordNet®

wolfsbane
     n : poisonous Eurasian perennial herb with broad rounded leaves
         and yellow flowers and fibrous rootstock [syn: {wolfbane},
          {wolf's bane}, {Aconitum lycoctonum}]