| Abbreviation | Definition |
|---|---|
| ORSC | Old Republic Surety Company |
| ORSTO | Option Reactive System Technology Output |
| ORTC | Old Republic Title Company |
| ORU | Off Road Unlimited |
| ORU | Orange and Rockland Utilities |
| ORV | Orthopaedic Research of Virginia |
| ORW | OffRoad Warehouse |
| OS | OmniSky |
| OS | out of stock |
| OSBC | Odisha State Beverage Corporation |
| OSBC | Osun State Broadcasting Corporation |
| OSBI | One Step Beyond Inc |
| OSC | Off-Shore Company |
| OSC | Online Services Corporation |
| OSCA | Officine Specializzate Costruzioni Automobili |
| OSCI | Ordinary Sales Company, Inc. |
| OSCR | Oregon Soil Corporation Reactor |
| OSD | Operational Services Division |
| OSD | Outdoor Speaker Depot |
| OSE | Offshore Software Engineering |