n., pl., -ni·ons, or -ni·a (-nē-ə).
A thin, tough, membranous sac that encloses the embryo or fetus of a mammal, bird, or reptile. It is filled with a serous fluid in which the embryo is suspended.
[Greek amniōn.]
amniotic am'ni·ot'ic (-ŏt'ĭk) or am'ni·on'ic (-ŏn'ĭk) adj.
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
