| Abbreviation | Definition |
|---|---|
| NAOI | National Association of Online Investors |
| NAS | No Age Statement |
| NASD | National Association of Securities Dealers |
| NASDAQ | National Association of Securities Dealers Automated Quotations |
| NAV | Net Asset Value |
| NAV.ENG. | naval engineer(ing) |
| NB | Net Business |
| NB | Nights Booked |
| NBC | National Business Committee |
| NBC | Never Be Complacent |
| NBC | No Big Changes |
| NBD | New Business Development |
| NBFU | National Board of Fire Underwriters (1866–1965 when it became the AIA and phased out its technical activities and its contributions to fire protection engineering) |
| NBH | Next Business Hour |
| NBIC | Nashville Business Incubation Center |
| NBK | New Business And Knowledge |
| NBM | National Bank of Moldova |
| NBO | National Business Ordering |
| NBR | Nightly Business Report |
| NBV | New Business Venture |