Webster's Revised Unabridged Dictionary · 1913

Ectoblast

Ectoblast , noun

[Ecto- + Greek {not transcribed} bud, germ.]

(a)
(Biology) The outer layer of the blastoderm; the epiblast; the ectoderm.
(b)
(Biology) The outer envelope of a cell; the cell wall. — Agassiz