/ Dictionary / Index E ectoderm: Meaning and Definition of Find definitions for: ec•to•derm Pronunciation: (ek'tu-dûrm"), [key] — n. Embryol. the outer germ layer in the embryo of a metazoan. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: ectoderm (Thesaurus) ectocornea ectoenzyme Related Content Daily Word Quiz: mamba Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language