- AO stands for (USN Rating) Aviation Ordnanceman
- AO stands for Aaron Owens (streetball player)
- AO stands for Abdominal Obesity
- AO stands for Abgabenordnung (German tax regulations)
- AO stands for Abnormal Occurrence
- AO stands for Abort Output (TELNET protocol)
- AO stands for Academy of Osseointegration
- AO stands for Access Opening
- AO stands for Access Ordering
- AO stands for Accommodation Officer
- AO stands for Accompanying Object
- AO stands for Account Of
- AO stands for Account Owner
- A/O stands for Accounting Only
- AO stands for Accounts Office
- AO stands for Accredited Organization
- AO stands for ACCS (Army Command and Control System) OSI (Operator System Interface)
- A/O stands for Acoustic/Optic (spectroscopy)
- AO stands for Acousto Optics
- AO stands for Acquisition Objective
- AO stands for Acridine Orange
- AO stands for Acronym Overload
- AO stands for Action Officer
- AO stands for Action Oriented
- AO stands for Active Optical
- AO stands for Adaptive Onestep (IEEE)
- AO stands for Adaptive Optics
- AO stands for Adjustable Objective (rifle telescopic sight)
- AO stands for Administration Officer
- AO stands for Administrative Office/ Officer
- AO stands for Administrative Order
- AO stands for Admit One
- AO stands for Adults Only
- AO stands for Adults Only (ESRB game rating, 18 yrs. and up; graphic sex/violence)
- AO stands for Advanced Organization (Church of Scientology)
- AO stands for Advisory Opinion
- AO stands for Aerial Observer
- AO stands for Aeronautical Orders (orders authorizing a military person to perform duties in flight)
- AO stands for Aerosol Obscurant
- AO stands for Afrique Orientale (German East Africa)
- AO stands for Age Old
- AO stands for Agent Orange (herbicidal warfare)
- AO stands for Air Observer
- AO stands for Air Officer
- AO stands for Air Operation
- AO stands for Air Overseas, Inc.
- AO stands for Aircraft Operator
- AO stands for Airdrome Officer
- A/O stands for Alert and Oriented (charting a patient’s mental status)
- AO stands for Alexander Ovechkin (hockey player)
- AO stands for All Out
- AO stands for Alpha et Omega (epigraphy)
- AO stands for Ambient Occlusion (graphics)
- AO stands for Ambleside Online (homeschool curriculum)
- AO stands for Ambulance Officer (ambulance service; chiefly Australian)
- AO stands for American Optical
- AO stands for American Outfitters (store)
- AO stands for American Outlaws (soccer fan group)
- AO stands for Among Others
- AO stands for Amphibious Operation
- AO stands for Analog Output
- A/O stands for Analog Output
- AO stands for Anarchy Online (internet game)
- AO stands for Anarchy-Online (PC MMORPG)
- AO stands for And Others
- AO stands for Anglicans Online
- AO stands for Angola
- AO stands for Annotated Outline
- AO stands for Announcement of Opportunity
- AO stands for Annoying Orange (Youtube channel)
- AO stands for Anodal Opening
- AO stands for Answers Only (educational testing)
- AO stands for AntiOnline (computer security website)
- AO stands for Anti-Oxidant
- AO stands for Aortagram
- AO stands for Aosta (Val d’Aosta, Italy)
- AO stands for Apostolic Oblates
- AO stands for Appeals Office(r)
- AO stands for Application Object
- AO stands for Application Outsourcing
- AO stands for Applied Optics
- AO stands for Approximate Optimum Method
- AO stands for Arbeitsgemeinschaft für Osteosynthesefragen (Association for the Study of Internal Fixation)
- AO stands for Archives of Ontario
- AO stands for Arctic Ocean
- AO stands for Arctic Oscillation
- AO stands for Area of Operation
- A/O stands for Area of Operations
- AO stands for Area Office
- AO stands for Argentum Online
- AO stands for Arkansas and Ozarks Railway
- A/O stands for As Of
- AO stands for Asia Onlus (Rome, Italy)
- AO stands for Assembly Order
- AO stands for Assessing Officer (tax; India)
- AO stands for Assessment Objective
- AO stands for Assignment Officer
- AO stands for Assisted Opener (type of knife)
- AO stands for Assisted Operations
- AO stands for Associate Office
- AO stands for Associate Post Office (also called associate office)
- AO stands for Associated Object
- AO stands for Association Orukutuku
- AO stands for Asylum Officer (US DHS)
- A/O stands for At Once
- AO stands for Atelosteogenesis
- AO stands for Athlitikos Omilos (Greek: Athletic Club)
- AO stands for Atlantic Ocean
- AO stands for Atlanto-Occipital (joint)
- AO stands for Atlas Orthogonal (chiropractic technique; also seen as AOT)
- AO stands for Atmosphere-Ocean
- AO stands for Atomic Operation
- AO stands for Atomic Orbital
- AO stands for Atomic Oxygen
- A/O stands for Atomic Weight Percent
- AO stands for Attack Objective
- AO stands for Attendees Only
- AO stands for Atualidades Ornitológicas (Ivaiporã-PR, Brazil)
- AO stands for Audit Office
- AO stands for Auslandsorganisation (foreign section of NSdAP)
- AO stands for Australian Airlines (IATA airline code)
- AO stands for Australian Open (tennis tournament)
- AO stands for Authentic Orginal (retail)
- AO stands for Authorized Outage
- AO stands for Authorizing Official (for IMPAC Purchases)
- AO stands for Automags Online
- AO stands for Automated Office
- AO stands for Automated Operations
- AO stands for Autonomous Okrug
- AO stands for Autres Objets (Canada universal postal union)
- AO stands for Auxiliary Oiler (Ship Type)
- AO stands for Auxiliary Operator (nuclear industry)
- AO stands for Aviation Officer
- AO stands for Aviation Ordnance Person (US DoD)
- AO stands for Awards and Obligations
- AO stands for Fly Outs (baseball statistic)
- AO stands for Office of the Administrator
- AO stands for Officer of the Order of Australia
- AO stands for Operational Availability
- AO stands for Order of Australia
- AO stands for Other Articles (US postal service)
A/O