area of responsibility 
Atlantic Ocean Region 
Astronomical Observation Request 
Association of Realtors 
Atlantic Operating Region 
Replenishment Oiler 
abnormal occurrence report 
acknowledgment of receipt 
Address of Record 
adjusted odds ratio 
Adjusted odds ratios 
adjusted OR 
After Outliers Removed 
after-operations recovery 
Age of Renaissance 
age-adjusted odds ratio 
Agent Orange Registry 
Album Oriented Rock 
aldehyde ferredoxin oxidoreductase 
Aldehyde oxidoreductase 
Aliquippa and Ohio River Railroad 
alternate opacity request 
anchor order 
Angle of Reflection 
annual operating requirement 
Annual Operating Requirements 
Annual Operation Requirements 
aortic root 
Application Owning Region 
Arctic and Offshore Research