/ Dictionary / Index D diacaustic: Meaning and Definition of Find definitions for: di•a•caus•tic Pronunciation: (dī'u-kô'stik), [key] — Math., Math.,Optics. —adj. noting a caustic surface or curve formed by the refraction of light. —n. a diacaustic surface or curve. Cf. catacaustic. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. diabolo diacetic acid Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language