| Acronym | Definition |
|---|
| ACU | Australian Catholic University |
| ACU | Abilene Christian University (formerly Abilene Christian College; Abilene, TX, USA) |
| ACU | Army Combat Uniform |
| ACU | Association of Commonwealth Universities (UK) |
| ACU | American Conservative Union |
| ACU | Array Configuration Utility |
| ACU | Association of Clinicians for the Underserved |
| ACU | Assault Craft Unit |
| ACU | Antenna Control Unit |
| ACU | Auto Cycle Union (UK) |
| ACU | Aironet Client Utility (Cisco tool for managing wireless profiles for use with Aironet PC cards) |
| ACU | Asian Clearing Union |
| ACU | Automatic Calling Unit |
| ACU | Air Conditioning Unit |
| ACU | Armored Command Unit (gaming; Supreme Commander) |
| ACU | Alliance Credit Union (various locations) |
| ACU | Amtscentret for Undervisning |
| ACU | Auto Call (Calling) Unit |
| ACU | Alarm Control Unit |
| ACU | Agrupacion Catolica Universitaria |
| ACU | Advanced Combat Uniform |
| ACU | Acquisition Control Unit |
| ACU | Automóvil Club del Uruguay |
| ACU | Audio Control Unit |
| ACU | Automatic Client Update |
| ACU | Attitude Control Unit |
| ACU | Avionics Control Unit |
| ACU | Auxiliary Control Unit |
| ACU | Acknowledgement Signal Unit |
| ACU | Antenna Coupler Unit |
| ACU | Arithmetic & Control Unit |
| ACU | Arm Computer Unit (NASA) |
| ACU | Address Calculation Unit (digital electronics) |
| ACU | Amstrad Computer User (Amstrad CPC magazine) |
| ACU | Aircraft Control Unit |
| ACU | Area Common User |
| ACU | American Church Union |
| ACU | Acceleration Control Unit |
| ACU | Autopilot Control Unit (aviation) |
| ACU | Atlantic Council of Ukraine |
| ACU | Apron Control Unit (aviation) |
| ACU | Army Common User |
| ACU | Actors' Church Union (Church of England organisation for the entertainment industry) |
| ACU | Automatic Calibration Unit |
| ACU | Awaiting Class Up |
| ACU | Assistant C/Unix |
| ACU | Air Cleanup Unit |
| ACU | Alarm Concentration Unit |
| ACU | Air Compressor Unit |
| ACU | Ambulatory Cardiac Unit |
| ACU | Alarm Collection Unit |
| ACU | Antenna Combinary Unit |
| ACU | Association Centre Univers |
| ACU | Analog Conversion Unit |
| ACU | Automatic Coil Unwinder |
| ACU | Amplifier Converter Unit |
| ACU | Airspace Coordination Unit (various locations) |
| ACU | African Cinema Unit (University of Cape Town; South Africa) |