/ Dictionary / Index D demento: Meaning and Definition of Find definitions for: de•ment•o Pronunciation: (di-men'tō), [key] — pl. -ment•os. a deranged, mentally disturbed, or fanatic person; lunatic; nut. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. dementia praecox demerara Related Content Daily Word Quiz: belligerent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language