| Abbreviation | Definition |
|---|---|
| UCX | Universal Communications X |
| UD | United Devices |
| UDA | United Design Associates |
| UDA | Upper Deck Authentic |
| UDB | United Drill Bushing |
| UDC | Uganda Development Corporation |
| UDC | United Discount Chemists |
| UDC | Universal Display Corporation |
| UDC | University Development Centre |
| UDC | Urban Development Company |
| UDC | Urban Development Corporation |
| UDC | Utility Distribution Company |
| UDCN | UDC Homes, Inc. |
| UDE | Upper Deck Entertainment |
| UDG | Ultimate DJ Gear |
| UDH | Unique Dallas Homes |
| UDHI | Union Dental Holdings, Inc. |
| UDI | UmweltDirektInvest-Beratungs, GmbH |
| UDI | United Defense Industries, Inc. |
| UDI | Universal Data Inc |