/ Dictionary / Index D De Morgan: Meaning and Definition of Find definitions for: De Mor•gan Pronunciation: (di môr'gun), [key] 1806–71, English mathematician and logician. 1839–1917, English novelist and ceramist. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. demoralize De Morgan's laws Related Content Daily Word Quiz: topography Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language