| Acronym | Definition |
|---|
| RAO | Radio Receiver (US Navy) |
| RAO | Regulated Activities Order |
| RAO | Rechtsanwaltsordnung (German: Lawyers' Act; Austria) |
| RAO | Right Anterior Oblique (Radiologic Term) |
| RAO | Recurrent Airway Obstruction |
| RAO | Retiree Activities Office |
| RAO | Research and Advocacy Organization |
| RAO | Retinal Artery Occlusion |
| RAO | Response Action Outcome (Massachusetts and New Jersey) |
| RAO | Recent African Origin (paleoanthropology) |
| RAO | Réponse À Appel d'Offres (French: Tender Response) |
| RAO | Research Administration Officer (Australia) |
| RAO | Race across Oregon (bicycling) |
| RAO | Russian Archives Online |
| RAO | Ribeirao Preto, Sao Paulo, Brazil (Airport Code) |
| RAO | Research Analysis Office |
| RAO | Remedial Action Objective |
| RAO | Response Amplitude Operator (mechanical engineering) |
| RAO | Royal Army of Oman |
| RAO | Regional Accounting Office |
| RAO | Registration Authority Operator |
| RAO | Recherche Assistée par Ordinateur (French: Computer Assisted Research) |
| RAO | Rassemblement des Astrologues Occidentaux (French: Gathering of Western Astrologers) |
| RAO | Regional Aviation Officer (US Forest Service position) |
| RAO | Resident Arts Organization (various locations) |
| RAO | ReadAllOver (image file format) |
| RAO | Resource Analysis Office |
| RAO | Read As One |
| RAO | Réflexion Assistée par Ordinateur (French: Computer Assisted Puzzle) |
| RAO | Rhône Alpes Orchidées (French: Rhone Alps Orchids; est. 1987) |
| RAO | Right Ascension Offset |
| RAO | Regimental Administration Office (BATUS) |
| RAO | Regimental Activities Officer |
| RAO | Residential Actions Office (US military) |
| RAO | Resident Agent Office |
| RAO | Rating Assignment Office (US Navy) |
| RAO | Rhône Alpes Outillage (French: Rhone Alps Tools) |