| Abbreviation | Definition |
|---|---|
| NDRS | Northern Drag Racing Series |
| NEAR | New England Antique Racing |
| NGTR | Nigel Griffiths Thoroughbred Racing |
| NHFTHR | No Hope For The Human Race |
| NHRA | No Hotrod Racing Allowed |
| NHRA | Not Helping Racers Achieve |
| NIRA | National Import Racing Association |
| NIRA | National Inline Racing Association |
| NIRA | National In-line Racing Association |
| NMRC | New Mexico Racing Commission |
| NOOD | National Offshore One Design race |
| NOR | Non-Organized Racing |
| NORDA | New Orleans Racing Drivers Association |
| NORRA | National Off Road Racing Association |
| NR | New Racing |
| NRC | Nantahala Racing Club |
| NRC | National Racing Calendar |
| NRE | Nelson Racing Engines |
| NRE | Non-Racing Event |
| NRFHT | Non Reassuring Fetal Heart Tracing |