Definition of "epiblast" [ep•i•blast]

• The outer layer of a blastula that gives rise to the ectoderm after gastrulation. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "It has long been known that certain cells of an early mammalian embryo—known as epiblast cells—can naturally become primordial germ cells, which, in turn, give rise to sperm or eggs."
• "It has long been known that certain cells of an early mammalian embryo -- known as epiblast cells -- can naturally become primordial germ cells, which, in turn, give rise to sperm or eggs."
• "During mouse embryo development, the blastocyst differentiates into pluripotent primitive ectoderm and gives rise to a structure known as the epiblast"