/ Dictionary / Index P protoderm: Meaning and Definition of Find definitions for: pro•to•derm Pronunciation: (prō'tu-dûrm"), [key] — n. Bot. a thin outer layer of the meristem in embryos and growing points of roots and stems, which gives rise to the epidermis. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. protodeacon proto-Doric Related Content Daily Word Quiz: cygnet Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language