| Abbreviation | Definition |
|---|---|
| AADS | Admission Avoidance & Discharge Services |
| AAGBI | Association of Anaesthetists of Great Britain and Ireland |
| AAMI | age-associated memory impairment |
| AAMS | Association of Air Medical Services (US) |
| AAO | age at onset |
| AAO | American Academy of Osteopathy |
| AAO | American Academy of Otolaryngology. |
| AAO | American Association of Ophthalmology |
| AAOX3 | awake, alert and oriented to date, place and person |
| AAP | Alanyl aminopeptidase, ANPEP, EC 3.4.11.2 (CD13) |
| AAP | American Academy of Pedodontics |
| AAP | American Academy of Periodontists |
| AAS | abdominal aortic surgery |
| AAS | Abuse Assessment Screen |
| AAS | acid aspiration syndrome |
| AAS | AIDS Attitude Scale amino acid sequence |
| AAS | alcohol abstinence syndrome |
| AAS | Alcohol Action Service |
| AAS | allergic Aspergillus sinusitis |
| AAS | androgenic anabolic steroid |