/ Dictionary / Index N NSA: Meaning and Definition of Find definitions for: NSA Pronunciation: [key] National Security Agency. National Shipping Authority. National Standards Association. National Student Association. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: nsa (Thesaurus) NS NSC Related Content Daily Word Quiz: deleterious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language