/ Dictionary / Index I isidioid: Meaning and Definition of Find definitions for: i•sid•i•oid Pronunciation: (ī-sid'ē-oid"), [key] — adj. of, pertaining to, or resembling an isidium. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Isiac isidium Related Content Daily Word Quiz: spectral Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language