| Abbreviation | Definition |
|---|---|
| UMP | Uber0n Media Player |
| UMP | Ultralight MIDI Player |
| UMS | Unit Management Software |
| UMS | Universal Modding Studio |
| UMS | User Mode Scheduler |
| UMT | Ultimate Mail Tool |
| UNCOL | Universal Computer Oriented Language |
| UND | undetermined |
| UNFP | User Notes on FORTRAN Programming |
| UNL | Universal Network Language |
| UNMS | Ubiquiti Network Management System |
| UNO | Universal Network Objects |
| UNOS | University of Newcastle Operating System |
| UNRRDU | Utah Nearly Raw Raster Data Utilities |
| UOG | Utility Optimization Group |
| UOP | Ultima Online Portal |
| UOX | Ultima Offline eXperiment |
| UP | Unified Process |
| UPC | Unified Parallel C |
| UPC | University Programming Council |