| Acronym | Definition |
|---|
| CAO | Chief Administrative Officer (corporate title) |
| CAO | Central Applications Office (student placements in Irish universities) |
| CaO | Calcium Oxide |
| CAO | Conception Assistée par Ordinateur (French: Computer-Aided Design) |
| CAO | County Administrative Officer |
| CAO | Collectieve Arbeidsovereenkomst (Dutch) |
| CAO | Chief Accounting Officer (job title) |
| CAO | Chief Academic Officer |
| CAO | County Assistance Office (Pennsylvania) |
| CAO | Contract Administration Office(r) |
| CAO | Canadian Association of Optometrists |
| CAO | Cleanup and Abatement Order |
| CAO | Community Action Organization (Buffalo, NY) |
| CAO | Commission d'Appel d'Offres (France) |
| CAO | Current As Of |
| CAO | China Aviation Oil (Singapore) Corporation Ltd. |
| CAO | Canadian Association of Orthodontists |
| CAO | Computer-Assisted Ordering |
| CAO | Computer-Aided Optimization |
| CAO | County Attorney's Office |
| CAO | Cultural Affairs Officer (U.S. State Department, Public Affairs) |
| CAO | Carlsbad Area Office |
| CAO | Civil Aviation Order |
| CAO | Corrective Action Order |
| CAO | Cargo Aircraft Only |
| CAO | Cano A. Ozgener (cigar) |
| CAO | Chief Analytics Officer |
| CAO | Customs Administrative Order (Philippines) |
| CAO | Central Accounting Office |
| CAO | Casualty Assistance Office |
| CAO | Club Atlético Osasuna (Spanish football team) |
| CAO | Concentrated Animal Operation (Pennsylvania) |
| CAO | Civil Affairs Operations (US DoD) |
| CAO | Centre Afrika Obota (French; African development group) |
| CAO | Competency Aligned Organization (NAVAIR) |
| CAO | Center for Applied Optics (University of Alabama; Huntsville, AL) |
| CAO | California Academy of Ophthalmology |
| CAO | Customer Assistance Office |
| CAO | Correct Answer Only (examination marking schemes) |
| CAO | Change of Appointing Office (manpower/personnel) |
| CAO | Chukotka Autonomous Okrug (Russian region) |
| CAO | Combat Air Operations |
| CAO | Classification Advisory Officer (US NSA) |
| CAO | Counter Air Operation |
| CAO | Coordination of Atomic Operations |
| CAO | Central Asia Ovtcharka (dog breed) |
| CAO | Catering for All Occasions (Estes Park, CO) |
| CAO | Conscious, Alert, and Oriented |
| CAO | Command Assist Official |
| CAO | Case Administering Office (US Foreign Military Sales) |
| CAO | counterair operation (US DoD) |
| CAO | Collateral Action Office(r) |
| CAO | Crisis Action Officer |
| CAO | Contract Administrative Officer |
| CAO | Cost Analysis Organization |
| CAO | Circum-Atlantic Project |
| CAO | Corrections Auxiliary Officer |
| CAO | Chief Advisement Officer |
| CAO | Cercle d'Aviron Oléronais (French rowing club; Chateau d'Oleron, France) |
| CAO | College Art Online (Paradise Valley, AZ) |
| CAO | Central Adjudication Office |
| CAO | Civil Aviation Organisation (various locations) |
| CAO | Central Auditing Organization (Egypt) |
| CAO | Camarillo Academic Olympics (California) |