| Abbreviation | Definition |
|---|---|
| OB | Order of Battle |
| OBC | Obey Before Complain |
| OBC | Officer Basic Course |
| OBC | On Board Courier |
| OBC | Optical Bar Camera (U-2 sensor) |
| OBC | Ordnance Basic Course |
| OBD | Officer Battle Dossier |
| OBD | On Board Diagnostic |
| OBD | On-Board |
| OBD | Overboard |
| OBDM | Order of Battle Data Management |
| OBE | Overcome by Events |
| OBE | Overtaken By Events |
| OBF | Operation] Building Resilience and Valuing Empowered [Families] |
| OBFCS | On-Board Fire Control System |
| OBFS | Offshore Bulk Fuel System |
| OBHOJ | On Board Home On Jam |
| OBI | Order of British India |
| OBJ | Objective |
| OBL | OBLigated funding |