/ Dictionary / Index E endosperm: Meaning and Definition of Find definitions for: en•do•sperm Pronunciation: (en'du-spûrm"), [key] — n. Bot. nutritive matter in seed-plant ovules, derived from the embryo sac. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: endosperm (Thesaurus) endosome endospore Related Content Daily Word Quiz: gregarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language