/ Dictionary / Index N NAD: Meaning and Definition of Find definitions for: NAD Pronunciation: [key] — Biochem. Biochem. nicotinamide adenine dinucleotide: a coenzyme, CHNOP, involved in many cellular oxidation-reduction reactions. N.A.D. Pronunciation: [key] National Academy of Design. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: nad (Thesaurus) nacreous cloud Nadab Related Content Daily Word Quiz: banshee Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language