| A/A/O | Anaerobic/Anoxic/Oxic 
| Others |
| AAO | Add And Overflow
| Others |
| AAO | Add Another One
| Others |
| AAO | Administrative Appeals Office
| Others |
| AAO | Advanced Acoustic Optimisation
| Others |
| AAO | Advanced Acoustic Optimization
| Others |
| AAO | Advanced Acoustics Optimization
| Others |
| AAO | Adverse Assumption Obstacle
| Others |
| AAO | Affirmative Action Officer
| Others |
| AAO | Against All Odds
| Others |
| AAO | Agenda at Once
| Others |
| AAO | Air Access Only
| Others |
| AAO | Aktions Analytische Organisation
| Others |
| AAO | Alert Awake Oriented
| Others |
| AAO | All At Once
| Others |
| AAO | All At Onceness
| Others |
| AAO | Alt Approving Official
| Others |
| AAO | Alt Aproving Official
| Others |
| AAO | Am Angegebenen Ort
| Others |
| AAO | American Academy of Ophthalmology
| Others |
| AAO | American Academy of Optometry
| Others |
| AAO | American Academy of Osteopathy
| Others |
| AAO | American Academy of Otolaryngology
| Others |
| AAO | American Academy of Otolaryngology.
| Others |
| AAO | American Association of Ophthalmology
| Others |
| AAO | American Association of Orthodontists
| Others |
| AAO | Amino Acid Oxidase
| Others |
| AAO | Amphenol Aerospace Operations
| Others |
| AAO | An Amber Original
| Others |
| AAO | Anodic Aluminium Oxide
| Others |
| AAO | Anodic Aluminum Oxide
| Others |
| AAO | Anodized Aluminum Oxide
| Others |
| AAO | Approved acquisition objective
| Others |
| AAO | Arab Advertising Organization
| Others |
| AAO | Arabidopsis aldehyde oxidase
| Others |
| AAO | Archives Association of Ontario
| Others |
| AAO | Arkansas Athletes Outreach
| Others |
| AAO | Army Acquisition Objective
| Others |
| AAO | Ashtabula Art Online
| Others |
| AAO | Assassin Alliance Organization
| Others |
| AAO | Assistant Administrative Officer
| Others |
| AAO | Assistant Agriculture Officer
| Others |
| AAO | Assistant Ambulance Officer
| Others |
| AAO | Assistant Audit Officer
| Others |
| AAO | Association of Architecture Organizations
| Others |
| AAO | Association of Aviation Ordnancemen
| Others |
| AAO | Association of the Apartment Owners
| Others |
| AAO | Asst Administrative Officer
| Others |
| AAO | Assumed adverse obstacle
| Others |
| AAO | Authorized Acquisition Objective
| Others |
| AAO | Colonel James Jabara Airport, Wichita, Kansas USA
| Others |