| Abbreviation | Definition |
|---|---|
| OACETT | Ontario Association Of Certified Engineering Technicians And Technologists |
| OAFC | Ontario Association Of Fire Chiefs |
| OAFC | Ormohio Association Of Free Clinics |
| OAH | Organization of American Historians |
| OANA | Oklahoma Association of Nurse Anesthetists |
| OAO | Ontario Association of Optometrists |
| OAO | Opticians Association of Ohio |
| OAOB | Ohio Association Of Broadcasters |
| OAOB | Oregon Association Of Broadcasters |
| OAOP | Oklahoma Association of Optometric Physicians |
| OAP | Ohio Association of Parliamentarians |
| OAPE | Ohio Association of Polygraph Examiners |
| OAPHD | Ontario Association of Public Health Dentistry |
| OAPO | Ontario Association of Prosthetists and Orthotists |
| OAPSE | Ohio Association Of Public School Employees |
| OAPSE | Oyeesohio Association Of Public School Employees |
| OAQ | Ordre des Architectes du Québec |
| OASBO | Ohio Association of School Business Officials |
| OASBO | Ontario Association of School Business Officials |
| OASBO | Oregon Association of School Business Officials |