N
| Na | sodium (an electrolyte) |
| NB | Newborn |
| NCV | Nerve conduction velocity |
| NG | Nasogastric |
| NIDDM | Non–insulin-dependent diabetes mellitus |
| NIHL | Noise-induced hearing loss |
| NK cell | Natural killer cell |
| NMT | Nebulized mist treatment |
| NPH | Neutral protamine Hagedorn (insulin) |
| NPO, n.p.o.* | Nothing by mouth |
| NSAIDs | Nonsteroidal anti-inflammatory drugs |
| NSR | Normal sinus rhythm |
