/ Dictionary / Index D diene: Meaning and Definition of Find definitions for: di•ene Pronunciation: (dī'ēn, dī-ēn'), [key] — n. Chem. any compound, as 1,3-butadiene, CH=CH−CH=CH, that contains two double bonds. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. diencephalon die-off 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