| Acronym | Definitions |
|---|---|
| N/A | 3 |
| n/b | 2 |
| N/E | 3 |
| N/P | 1 |
| N/T | 2 |
| N/V | 2 |
| N/V/D/C | 1 |
| N1 | 3 |
| N2 | 3 |
| N2O | 1 |
| N2O5 | 2 |
| NA | 38 |
| NAA | 14 |
| NAAACPA | 1 |
| NAAB | 2 |
| NAACCR | 1 |
| NAACP | 2 |
| NAADA | 2 |
| NAADAC | 2 |
| NAAEC | 1 |
| NAAF | 2 |
| NAAFA | 2 |
| NAAG | 3 |
| NAAI | 2 |
| NAAP | 4 |
| NAAQS | 2 |
| NAAR | 2 |
| NAARS | 2 |
| NAAS | 6 |
| NAB | 10 |
(31 — 60 of 1623)