Source : Webster's Revised Unabridged Dictionary (1913)

Mullein \Mul"lein\, n. [OE. moleyn, AS. molegn.] (Bot.)
   Any plant of the genus {Verbascum}. They are tall herbs
   having coarse leaves, and large flowers in dense spikes. The
   common species, with densely woolly leaves, is {Verbascum
   Thapsus}.

   {Moth mullein}. See under {Moth}.

   {Mullein foxglove}, an American herb ({Seymeria macrophylla})
      with coarse leaves and yellow tubular flowers with a
      spreading border.

   {Petty mullein}, the cowslip. --Dr. Prior.

Source : WordNet®

mullein
     n : any of various plants of the genus Verbascum having large
         usually woolly leaves and terminal spikes of yellow or
         white or purplish flowers [syn: {flannel leaf}, {velvet
         plant}]