| ORS | olfactory reference syndrome; oral rehydration solution; oral surgery, oral surgeon; Orthopaedic Res... |
|---|---|
| ACS | acrocallosal syndrome; acrocephalosyndactyly; acute chest syndrome; acute confusional state; Alcon C... |
| AHS | Academy of Health Sciences; African horse sickness; alveolar hypoventilation syndrome; American Hear... |
| AOS | American Ophthalmological Society; American Otological Society; anodal opening sound; anterior [o]es... |
| ARS | acquiescence response scale; adult Reye's syndrome; alcohol-related seizures; alizarin red S; Americ... |