What is "epiblast"

Epiblast \Ep"i*blast\, n. [Pref. epi- + -blast.] (Biol.) The outer layer of the blastoderm; the ectoderm. See Blastoderm, Delamination.

n. (context biology English) the outer layer of a blastula that, after gastrulation, becomes the ectoderm

In amniote animal embryology, the epiblast is one of two distinct layers arising from the inner cell mass in the mammalian blastocyst or from the blastodisc in reptiles and birds. It derives the embryo proper through its differentiation into the three primary germ layers, ectoderm, mesoderm and endoderm, during gastrulation. The amnionic ectoderm and extraembryonic mesoderm also originate from the epiblast.