Meaning of epiblast

ep•i•blast

Pronunciation: (ep'u-blast"), [key]
— n. Embryol.
  1. the primordial outer layer of a young embryo before the segregation of the germ layers, capable of becoming the ectoderm and containing cells capable of becoming the mesoderm and endoderm.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.