| AOCR | American Osteopathic College of Radiology; American Osteopathic College of Rheumatology |
|---|---|
| AOS | American Ophthalmological Society; American Otological Society; anodal opening sound; anterior [o]es... |
| APHA | American Protestant Hospital Association; American Public Health Association |
| ARS | acquiescence response scale; adult Reye's syndrome; alcohol-related seizures; alizarin red S; Americ... |
| ASCO | American Society of Clinical Oncology; American Society of Contemporary Ophthalmology |