| Oceanography and Marine Assessment | Academic & Science |
| Online Music Appreciation | Academic & Science |
| Office for Metropolitan Architecture | Academic & Science |
| Ontario Medical Association | Academic & Science |
| Online Marketing Agency | Business |
| One Madison Avenue | Business |
| Office of Management Assessment | Business |
| Officine Meccaniche Aeronautiche | Business |
| Oh My Allah | Community |
| Oregon Mediation Association | Community |
| Oregon Medical Association | Community |
| Orlando Museum of Art | Community |
| Oceanside Museum of Art | Community |
| Oklah Museums Association | Community |
| Ohio Motocross Association | Community |
| Operator Monitoring Assessment | Community |
| Obesity Medicine Association | Community |
| Orwin Manor Association | Community |
| Open Meta Archive | Computing |
| Outlook Mobile Access | Computing |
| Operation Management Applications | Computing |
| Oracle Management Agent | Computing |
| Online Manual Archive | Computing |
| Open Mandriva Association | Computing |
| Open Mashup Alliance | Computing |
| Online Marketing Association | Computing |
| Object Management Architecture | Electronics |
| Oh My Al | General |
| Oh My Awesome | General |
| Outer Margin Area | General |
| One Man Armyl | General |
| Office of Multicultural Affairs | General |
| Oil Monitoring Analyst | General |
| Oswalds Mill Audio | General |
| Optical Map Assembler | General |
| Ocular Motor Apraxia | General |
| Ohio Monongahela and Allegheny | General |
| Organic Manuka active | General |
| Outstanding Merchandising Achievement | General |
| Oral and Maxillofacial Associates | General |
| Oat Maize And Addition | General |
| Observations Minus Anal | General |
| Optical Multichannel Analyzer | General |
| Office of Multidisciplinary Activities | General |
| Oh My Alice | General |
| One Month Anniversary | General |
| Ohio Motorcoach Association | General |
| Eppley Airfield | Governmental |
| Open Mobile Alliance | Governmental |
| Office of Metropolitan Architecture | Governmental |
| One Mans Army | Governmental |
| Office Moving Alliance | Governmental |
| Operations and Maintenance, Army | Governmental |
| Operations Maintenance Army | Governmental |
| On My A** | Internet |
| Oculomotor apraxia | Medical |
| Object of My Affection | Messaging |
| Oklahoma Military Academy | Military and Defence |
| Office of Military Affairs (cia) | Military and Defence |
| Operation and Maintenance, Army | Military and Defence |
| Omaha, Nebraska USA | Regional |
| Operations Maintenance Area | Space Science |
| Operations Management Application | Space Science |
| Orbiter Maintenance Area | Space Science |
| One Man Army | Sports |
| Oliver Martial Arts | Sports |