| 1 | UA | 21 definitions. |
| 2 | UC | 20 definitions. |
| 3 | UCC | 1 definition. |
| 4 | UCX | 1 definition. |
| 5 | UDS | 5 definitions. |
| 6 | UE | 7 definitions. |
| 7 | UF | 11 definitions. |
| 8 | UFH | 1 definition. |
| 9 | UMBO | 1 definition. |
| 10 | UMN | 1 definition. |
| 11 | UNSA | 1 definition. |
| 12 | UO | 4 definitions. |
| 13 | UPEP | 1 definition. |
| 14 | UPPP | 1 definition. |
| 15 | URI | 2 definitions. |
| 16 | US | 9 definitions. |
| 17 | UTD | 2 definitions. |
| 18 | UTI | 2 definitions. |
| 19 | UV | 6 definitions. |