from the GNU version of the Collaborative International Dictionary of English
- adj. a saccular appendage of the developing embryo, containing the nutritive and unsegmented part of the ovum; the yolk sac. See Illust. in Appendix.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functional
Sorry, no etymologies found.