| Abbreviation | Definition |
|---|---|
| UD | Unit Descriptor |
| UDAC | Unauthorized Disclosure Analysis Center |
| UDC | Unit Descriptor Code |
| UDD | Ultradispersive Detonational Diamond |
| UDESC | Unit Description |
| UDF | Ulster Defence Force |
| UDF | Ultimate Destruction Force |
| UDF | Un- Ducted Fan aircraft engine |
| UDF | Unit Data File |
| UDF | Unit Development Folder |
| UDF | United Digital Forces |
| UDI | Unique Device Identifier |
| UDID | Unique Data Item Description |
| UDL | Unit Designation List |
| UDL | United Deployment List |
| UDLP | United Defense Limited Partnership |
| UDMS | Unit Data Management System |
| UDP | Unit Deployment Package |
| UDP | Unit Deployment Program |
| UDP | Unitary Development Plan |