Source : Webster's Revised Unabridged Dictionary (1913)

Endoderm \En"do*derm\, n. [Endo- + Gr. ? skin.] (Biol.)
   (a) The inner layer of the skin or integument of an animal.
   (b) The innermost layer of the blastoderm and the structures
       derived from it; the hypoblast; the entoblast. See
       Illust. of {Ectoderm}.

Source : WordNet®

endoderm
     n : the inner germ layer that develops into the lining of the
         digestive and respiratory systems [syn: {entoderm}, {endoblast},
          {entoblast}, {hypoblast}]