/ Dictionary / Index E exoperidium: Meaning and Definition of Find definitions for: ex•o•pe•rid•i•um Pronunciation: (ek"sō-pu-rid'ē-um), [key] — pl. -rid•i•a the outer of the two layers into which the peridium is divided. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. exopeptidase exophasia 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