| Acronym | Definition |
|---|
| Au | Gold |
| Au | African Union (formerly Organization of African Unity) |
| Au | Air University (US Air Force) |
| Au | Australia (top-level domain name) |
| Au | Audio (file name extension) |
| Au | Author |
| Au | Audio Unit |
| Au | American University (Washington, DC, USA) |
| Au | Assessment Unit |
| Au | Austria |
| Au | Adelaide University (University of Adelaide, Australia) |
| Au | Anderson University (Indiana) |
| Au | Assumption University |
| Au | Alfred University |
| Au | Automatic (welding) |
| Au | Americans United (for the Separation of Church and State: Washington, DC) |
| Au | Autodesk University (online classes) |
| Au | Automatic Updates (Microsoft Windows) |
| Au | Astronomical Unit |
| Au | Auburn University (Auburn, Alabama) |
| Au | Alternate Universe |
| Au | Administrative Unit |
| Au | Aurora University |
| Au | Anna University (India) |
| Au | Aarhus Universit (University of Aarhus; Denmark) |
| Au | Ashland University |
| Au | Athabasca University |
| Au | Andrews University |
| Au | Authorized User |
| Au | Angeles University (Philippines) |
| Au | About Uncirculated (numismatics; coin condition) |
| Au | Adelphi University |
| Au | Aurum (Latin: Gold) |
| Au | Adamson University |
| Au | Aberdeen University (UK; aka University of Aberdeen; also seen as UoA) |
| Au | Aberystwyth University (Aberystwyth, UK) |
| Au | Ashford University (Clinton, IA) |
| Au | Access Unit |
| Au | Action Unit |
| Au | Avila University |
| Au | Annamalai University (India) |
| Au | Argosy University |
| Au | Adaptation Unit |
| Au | Andhra University (India) |
| Au | Accessible Unit |
| Au | Another Universe (comics) |
| Au | Ankara University |
| Au | Addressee Unknown |
| Au | Alopecia Universalis |
| Au | Associated Universities |
| Au | Alcohol Unit |
| Au | Anadolu University |
| Au | Acorn User (magazine) |
| Au | American Racing Pigeon Union (Oklahoma City) |
| Au | Arbitrary Unit |
| Au | Atomic Unit |
| Au | Atheists United |
| Au | Averett University (Danville, VA) |
| Au | Arithmetic Unit |
| Au | Adaptive Unit |
| Au | ATM User |
| Au | Always Usually |
| Au | Angstrom Unit |
| Au | Auxiliary Unit |
| Au | Amman University |
| Au | Associate in Underwriting (insurance) |
| Au | Unity Alliance (Nicaragua) |
| Au | Aquinas University |
| Au | Ambassador University |
| Au | Absorbance Unit |
| Au | Authors System |
| Au | Arellano University (Manila, Philippines) |
| Au | Aligarh University (India) |
| Au | Autistic/Autism |
| Au | Alignment Unit |
| Au | Analyzer Unit |
| Au | Apache University |
| Au | Araullo University |
| Au | Encoded Audio Format (file extension; Sun and NeXT) |
| Au | Auris Uterque (Latin: each ear) |
| Au | Automated Underwriter |
| Au | Authentication Unification (Sprint) |
| Au | Avionics Upper (panel) |
| Au | Anställningsutskottet (Swedish: Employment Committee) |