Webster’s Revised Unabridged Dictionary · 1913
Ectoblast
Ec′to·blast (ĕk′tō·blȧst), n. [Ecto- + Gr. βλαστός bud, germ.] (Biol.) (a) The outer layer of the blastoderm; the epiblast; the ectoderm. (b) The outer envelope of a cell; the cell wall. Agassiz.