/ Dictionary / Index N NRAB: Meaning and Definition of Find definitions for: NRAB Pronunciation: [key] National Railroad Adjustment Board. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. NRA NRC Related Content Daily Word Quiz: mamba Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language