embryo sac: Meaning and Definition of

em'bryo sac"

Pronunciation: [key]
— Bot. Bot.
  1. the megaspore of a seed-bearing plant, situated within the ovule, giving rise to the endosperm and forming the egg cell or nucleus from which the embryo plant develops after fertilization.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.