| LGA | large for gestational age; left gastric artery |
|---|---|
| NA | Avogadro constant or number; nalidixic acid; Narcotics Anonymous; network administrator; neuraminida... |
| NACSAP | National Alliance Concerned with School-Age Parents |
| OA | obstructive apnea; occipital artery; occipito-anterior; occiput anterior; octanoic acid; ocular albi... |
| OAA | Old Age Assistance; Older Americans Act; Opticians Association of America; oxaloacetic acid |