| Abbreviation | Definition |
|---|---|
| AS | Ascaris suum |
| AS | ascorbic acid |
| AS | assisted suicide |
| AS | atherosclerosis |
| AS | atrial septum |
| AS | attempted suicide |
| AS | audiogenic seizure |
| AS | audiovisual stimulation |
| ASA | acetylsalicylic acid |
| ASA | Adams-Stokes attack |
| ASA | alcohol septal ablation |
| ASA | Ambulance Service Association |
| ASA | American Society of Andrology |
| ASA | American Surgical Association |
| ASA | anterior septal artery |
| ASA | anterior spinal artery |
| ASA | antisperm antibody |
| ASA | atrial septal aneurysm |
| ASAP | Antioxidant Supplementation in Atherosclerosis |
| ASAP | apparatus for sensing accuracy of position |