(US, historical, 1930s) Initialism of National Recovery Act. / (UK) Initialism of National Rifle Association (of the United Kingdom). / (US) Initialism of National Rifle Association of America.

National Railway Adjustment Board.

(emergency medicine) Initialism of normal (rate and depth), regular rhythm, audible (breath sounds), rise and fall of chest, and pink skin color: signs of a patient with adequate breathing.

(astronomy, radio astronomy) Initialism of National Radio Astronomy Observatory.