Annual Operating Plan 
Air Observation Post 
Allied Ordnance Publication 
Aspect Oriented Programming 
Aspect-Oriented Programming 
Association of Online Professionals 
AUTOPART 
abnormal operating procedure 
Advanced Oxidation Process 
advanced oxidation processes 
air operations plan 
Approved Operating Program 
Area of Probability 
Army Order of Precedence 
Acacia Operation Project 
Academy of Oak Park 
Access Opportunity Programs 
Acknowledgment of Paternity 
Additive Operational Product/Project 
Additive Operational Project 
Additive Operational Projects 
Additive Ops Projects 
Advanced Observing Program 
Aerodrome Operations 
Aeronautical OSI Profile 
Aeropiloto 
Air Operating Permit 
Airborne Optics Platform 
Aircraft on Pier 
Airline Operational Procedure