| Abbreviation | Definition |
|---|---|
| NHS | Nut Hugger Syndrome |
| NIDS | Neuro Immune Deficiency Syndrome |
| NIDS | Neuroleptic Induced Deficit Syndrome |
| NJWAN | New Jersey Women and AIDS Network (Acquired Immune Deficiency Syndrome, AIDS) |
| NMS | Neonatal Maladjustment Syndrome |
| NNDS | Norwegian Network for Down Syndrome |
| NOFAS | National Organization on Fetal Alcohol Syndrome |
| NRDS | Newborn Respiratory Distress Syndrome |
| NRDS | Neonatal Respiratory Disease Syndrome |
| NRDS | Neonatal Respiratory Distress Syndrome |
| NS | Noonan Syndrome |
| NSML | Noonan syndrome with multiple lentigines |
| NSTEACS | non-ST-elevation acute coronary syndrome |
| OASN | Oral Allergy Syndrome Network |
| OBLA | Onset of Blood Lactate Accumulation |
| OCAS | Obsessive Campfire Adjustment Syndrome |
| ODS | Obstructed Defecation Syndrome |
| ODTS | Organic Dust Toxic Syndrome |
| ODTS | Organic Dust Toxicity Syndrome |
| OFDS | Oral Facial Digital Syndrome |