Source : Webster's Revised Unabridged Dictionary (1913)

Redhead \Red"head`\ (-h?d`), n.
   1. A person having red hair.

   2. (Zo["o]l.)
      (a) An American duck ({Aythya Americana}) highly esteemed
          as a game bird. It is closely allied to the
          canvasback, but is smaller and its head brighter red.
          Called also {red-headed duck}. {American poachard},
          {grayback}, and {fall duck}. See Illust. under
          {Poachard}.
      (b) The red-headed woodpecker. See {Woodpecker}.

   3. (Bot.) A kind of milkweed ({Asclepias Curassavica}) with
      red flowers. It is used in medicine.

Source : WordNet®

redhead
     n 1: someone who has red hair [syn: {redheader}, {red-header}, {carrottop}]
     2: North American diving duck with a gray-and-black body and
        reddish-brown head [syn: {Aythya americana}]
     3: black-and-white North American woodpecker having a red head
        and neck [syn: {redheaded woodpecker}, {Melanerpes
        erythrocephalus}]