/ Dictionary / Index D Diels: Meaning and Definition of Find definitions for: Diels Pronunciation: (dēlz Ger. dēls), [key] 1876–1954, German chemist: Nobel prize 1950. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. dielectric strength Diels-Alder reaction Related Content Daily Word Quiz: philtrum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language