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.
{ } a. (Biol.) Of or relating to the ectoderm. [ 1913 Webster ]