| Abbreviation | Definition |
|---|---|
| OIG | Office of Inspector General |
| OIPI | Office of Intermodal Planning and Investment |
| OIS | Operational Information system |
| OKC | Will Rogers World Airport |
| OKE | Over Kill Engine |
| OKH | Old King's Highway |
| OKS | Organisado, Kalinisan, y Seguridad (Organization, Cleanliness, and Security of busses) |
| OLBA | One Lane Bridge Ahead |
| OLEV | Office for Low Emission Vehicles |
| OLEV | Office of Low Emission Vehicles |
| OLEV | On Line Electric Vehicle |
| OLEV | On Line Electronic Vehicle |
| OLEV | Operation Lifesaver Educational Vehicle (rail safety; Canada) |
| OLEV | Orbital Live Extension Vehicle |
| OLT | On- Line Tracking |
| OLV | Outdoor Lifestyle Vehicle |
| OM | Official Mileage |
| OM | Old Model |
| OM | Outer Marker |
| OM | Owners Manual |