/ Dictionary / Index D diphthongia: Meaning and Definition of Find definitions for: diph•thon•gi•a Pronunciation: (dif-thông'ē-u, -gē-u, -thong'-, dip-), [key] — n. Pathol. diplophonia. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. diphthong diphthongize 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