| Abbreviation | Definition |
|---|---|
| TY2 | Gualtieri Theme Maker |
| TYM | PageMaker 4 Time Stamp |
| TZ | Compressed file archive.tar.Z ( Tar and Compress) |
| TZB | TAR - Compress - BTOA Compressed file archive.tar.Z.btoa |
| TZG | TRAC T84 language file |
| TZX | Sinclair ZX Spectrum game file |
| U | Subsampled raw YUV file Bitmap graphics |
| U4A | UnInstaller archive |
| U8 | Sample |
| UB | Music file Unsigned Byte |
| UBF | Ugl Bitmap Font |
| UBM | Iphoto Mtwain Install File |
| UBS | Tracesrv Bugslayer Utility File |
| UC2 | UltraCompressor II Compressed file archive |
| UCD | Use Case Diagram ( Prosa/OM) |
| UCF | Xilinx Foundation User Constraint File |
| UCN | UltraCompressor II New compressed file archive |
| UCS | Universal Classification Standard Database File |
| UDB | Microsoft Works File |
| UDB | Windows2000 Uniqueness Database File |