| Acronym | Definition |
|---|
| OR | Oregon (US postal abbreviation) |
| OR | Operating Room |
| OR | On Request |
| OR | O-Ring |
| OR | Outdoor Research |
| OR | Office of Record |
| OR | Official Records (Of the American Civil War; historical citations) |
| OR | Orange Range (Japanese rock band) |
| OR | Organization Administrator |
| OR | Object Reference (CORBA) |
| OR | Operating Range |
| OR | Open Repair |
| OR | Operations Research |
| OR | Operations Room |
| OR | Operations Requirements |
| OR | Operations Resources |
| OR | Ontario Reports |
| OR | Oak Ridge |
| OR | Officer Representative |
| OR | On-Site Representative |
| OR | Open Root (welding) |
| OR | Object Recognition |
| OR | Objective Response |
| OR | Optical Router |
| OR | Odds Ratio (element of statistical regression analysis, science) |
| OR | Overall Resistance |
| OR | Official Receipt |
| OR | Oxygen Reduction |
| OR | Olympic Record |
| OR | Operational Reserve |
| OR | Operational Review |
| OR | Operational Research |
| OR | Operational Requirement |
| OR | Operational Reliability |
| OR | Other Ranks (British military) |
| OR | Observed Ratio |
| OR | Outreach |
| OR | Optimal Routing (telecom) |
| OR | Onion Ring |
| OR | Overload Relay |
| OR | Occupancy Rate |
| OR | Object Reuse |
| OR | Occurrence Report |
| OR | Offensive Rebound (basketball) |
| OR | Organized Rhyme (rap group) |
| OR | Operational Readiness |
| OR | Override |
| OR | Object to Relational |
| OR | Operating Reactor |
| OR | Open Repositories (Conference) |
| OR | Outside Rehearsals |
| OR | Omani Rial (national currency) |
| OR | Operationally Ready |
| OR | Osservatore Romano (Vatican newapaper) |
| OR | Omnidirectional Range |
| OR | Orgone (energy) |
| OR | Ondernemingsraad |
| OR | Own Recognizance |
| OR | Over Rate (cricket scoring) |
| OR | Owner's Risk |
| OR | Owyhee River (Snake River; various locations) |
| OR | Onion Routing |
| OR | Omega Rho (honors society for Operations Researchers) |
| OR | Oristano, Sardegna (Italian province) |
| OR | Offence Report (police incident code; New Zealand) |
| OR | Originator / Recipient |
| OR | Outward Radial |
| OR | Ordinary Proton (event) |
| OR | Orthogonal Region |
| OR | Ordnance Requirement |
| OR | Owasco River Railroad |
| OR | Outward Routing |
| OR | Old Ruymian (alumni of Chatham House Grammar School for boys, Ramsgate, Kent, UK) |
| OR | Only Replication/Replicating |