/ Dictionary / Index N NIMH: Meaning and Definition of Find definitions for: NIMH Pronunciation: [key] National Institute of Mental Health. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Nîmes nimiety Related Content Daily Word Quiz: agitated Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language