/ Dictionary / Index D diad: Meaning and Definition of Find definitions for: di•ad Pronunciation: (dī'ad), [key] — n., adj. dyad. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. diactinic diadelphous Related Content Daily Word Quiz: supine Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language