Also found in: Thesaurus, Medical, Encyclopedia, Wikipedia.
Related to extraembryonic membrane: extraembryonic mesoderm
any of the membranes derived from embryonic tissue that lie outside the embryo, as the allantois, amnion, chorion, and yolk sac.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.