| Abbreviation | Definition |
|---|---|
| A/L | Annual Leave |
| A2LA | American Association for Laboratory Accreditation |
| AAALAC | Association for the Assessment and Accreditation of Laboratory Animal Care International |
| AAAP | American Association of Avian Pathologists |
| AAAS | American Association for the Advancement of Science |
| AABB | American Association of Blood Banks |
| AABP | American Association of Bovine Practitioners |
| AACR | American Association for Cancer Research |
| AADA | Abbreviated Antibiotic Drug Application |
| AAEP | American Association of Equine Practitioners |
| AAFCO | Association of American Feed Control Officials |
| AAFP | American Academy of Family Physicians |
| AAHA | American Animal Hospital Association |
| AAI | American Association of Immunologists |
| AALAS | American Association for Laboratory Animal Science |
| AANN | American Association of Neurosciences Nurses |
| AANS | American Association of Neurological Surgeons |
| AAO | American Academy of Ophthalmology |
| AAP | American Academy of Pediatrics |
| AAPHP | American Association of Public Health Physicians |