Source : Webster's Revised Unabridged Dictionary (1913)

Henbane \Hen"bane`\, n. [Hen + bane.] (Bot.)
   A plant of the genus {Hyoscyamus} ({H. niger}). All parts of
   the plant are poisonous, and the leaves are used for the same
   purposes as belladonna. It is poisonous to domestic fowls;
   whence the name. Called also, {stinking nightshade}, from the
   fetid odor of the plant. See {Hyoscyamus}.

Source : WordNet®

henbane
     n : poisonous fetid Old World herb having sticky hairy leaves
         and yellow-brown flowers; yields hyoscyamine and
         scopolamine [syn: {black henbane}, {stinking nightshade},
          {Hyoscyamus niger}]