/ Dictionary / Index E ectomere: Meaning and Definition of Find definitions for: ec•to•mere Pronunciation: (ek'tu-mēr"), [key] — n. Embryol. any of the blastomeres that participate in the development of the ectoderm. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. ectogenous ectomorph Related Content Daily Word Quiz: nonchalant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language