/ Dictionary / Index S soredium: Meaning and Definition of Find definitions for: so•re•di•um Pronunciation: (su-rē'dē-um), [key] — pl. -di•a a group of algal cells surrounded by hyphal tissue, occurring on the surface of the thallus and functioning in vegetative reproduction. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. soredial sorehead Related Content Daily Word Quiz: hedonist Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language