| Abkürzung | Bereich | Staat | Bedeutung |
| T | Physik | Periodendauer | |
| Temperatur | |||
| Torsionsmoment | |||
| t | Physik | Celsius-Temperatur | |
| Zeit | |||
| tan | Mathematik | Tangens | |
| TASM | Software | Turbo Assembler (Programmiersprache) | |
| TBK | Software | Toolbook | |
| TCP | Computer | Transmission Control Protocol (TCP/IP) | |
| TCP/IP | Computer | Transmission Control Protocol / Internet Protocol | |
| TD | Computer | Transmit Data | |
| TDE | Computer | Terminal Display Editor | |
| TDMS | Computer | Terminal Display Management System | |
| TE | Computer | Terminal Emulator | |
| TEC | Firma | J | Tokyo Electronics Corporation |
| teilmöbl. | Haus | D | teilmöbliert |
| Terr. | Haus | D | Terrasse |
| TFDD | Computer | Text File Device Driver | |
| TG | Haus | D | Tiefgarage |
| TI | Firma | USA | Texas Instruments Inc. |
| TID | Computer | Target ID | |
| TIFF | Software | Tagged Image File Format | |
| TIP | Computer | Terminal Interface Processor | |
| TM | Allgemein | Trademark (Warenzeichen) | |
| Tm | Einheit | Terameter | |
| TNC | Computer | Terminal Node Controller | |
| TP | Software | Turbo Pascal (Programmiersprache) | |
| TPORT | Technik | Twisted Pair Port Transceiver | |
| TPW | Software | Turbo Pascal for Windows | |
| TR | Computer | Task Register | |
| Terminal Ready | |||
| TSB | Computer | Termination Status Block | |
| TSO | Computer | Time Sharing Option | |
| TTF | Computer | True Type Font | |
| TÜV | Verein | D | Technischer Überwachungsverein |
| TV | Allgemein | D | Tennisverein |
| Turnverein | |||
| Technik | Television (Fernseher) | ||
| U | Physik | Spannung | |
| u | Physik | Geschwindigkeit | |
| u.s.w. | Allgemein | D | und so weiter |
| u.U. | Allgemein | D | unter Umständen |
| u.v.a. | Allgemein | D | und vieles andere |
| UDC | Computer | User Defined Commands | |
| UDF | Computer | User Defined Functions | |
| UDP | Computer | User Datagram Protocol | |
| UFDT | Computer | User File Descriptor Table | |
| UG | Computer | User Group | |
| UHF | Technik | Ultra High Frequency | |
| UI | Computer | User Interface | |
| UID | Computer | User Identifier | |
| UL | Computer | Upload | |
| UMB | Computer | Upper Memory Block | |
| URL | Computer | Universal Resource Protocol | |
| US | Staat | Unated Staates of America | |
| USA | Staat | Unated Staates of America | |
| USV | Technik | D | Unterbrechungsfreie Stromversorgung |
| usw. | Allgemein | D | und so weiter |
| UT | Computer | User Terminal | |
| UTP | Technik | D | Unshielded Twisted Pair |
| UV | Farbe | D | Ultraviolet |