Source : Webster's Revised Unabridged Dictionary (1913)

Ectoderm \Ec"to*derm\, n. [Ecto- + -derm.] (Biol.)
   (a) The outer layer of the blastoderm; epiblast.
   (b) The external skin or outer layer of an animal or plant,
       this being formed in an animal from the epiblast. See
       Illust. of {Blastoderm}.

Source : WordNet®

ectoderm
     n : the outer germ layer that develops into skin and nervous
         tissue [syn: {exoderm}, {ectoblast}]