| non-REM | non-rapid eye movement [sleep] |
|---|---|
| NREM | nonrapid eye movement [sleep] |
| NSD | Nairobi sheep disease; neonatal staphylococcal disease; neurosecretory dysfunction; night sleep depr... |
| OSA | obstructive sleep apnea; Office of Services to the Aging; Optical Society of America; ovarian sectio... |
| OSAS | obstructive sleep apnea syndrome |