Anglo-Australian Observatory 
American Academy of Ophthalmology 
amino acid oxidase 
Administrative Appeals Office 
American Academy of Optometry 
anodic aluminum oxide 
Army Acquisition Objective 
Authorized Acquisition Objective 
Academy of Ophthalmology 
Academy of Otolaryngology 
acute aortic occlusion 
Adjacent Arctic Ocean 
age at onset 
Alberta Association of Optometrists 
All At Once 
Amarillo Area Office 
American Academy of Osteopathy 
American Association of Ophthalmology 
American Association of Optometrists 
American Association of Orthodontists 
anodic aluminium oxide 
Anti-Air Output 
Army Acquisition Organization 
aryl-alcohol oxidase 
ascending aorta 
ascorbate oxidase 
ascorbic acid oxidase 
Astronaut Activities Office 
Australian Army Order 
Authorized Acquisition Officer