| UIL | User Interface Language |
| UIML | User Interface Markup Language |
| XUL | Extensible / XML-Based User Interface Language |
| OPL | Open user interface Presentation Language |
| UPL | User Program Language |
| UI | User Interface |
| XUI | X11 User Interface |
| UMI | User MAN Interface |
| UIM | User Interface Management |
| MUI | Magic User-Interface |
| FUI | Fake User Interface |
| UIP | User Interface Program |
| NUI | Notebook User Interface |
| XUI | X-windows User Interface |
| PUI | Picoscopic User Interface |
| UNI | User Network Interface |
| GUI | Graphical User Interface |
| VUI | Video User Interface |
| TUI | Text User Interface |
| UIS | User Interface Specification |
| AUI | Archiver User Interface |
| UIST | User Interface Software and Technology |
| UIMS | User Interface Management System |
| VUIT | Visual User Interface Tool [DEC] |
| UIDE | User Interface Development Environment |
| LUNI | LAN Emulation User Network Interface |
| CUI | Character/Common User Interface [IBM] |
| NETBEUI | NetBIOS Extended User Interface [IBM] |
| CUI | Captive/Consistent User Interface |
| TUI | Text-based User Interface |
| AGUI | Advanced Graphical User Interface [engl.] |
| AUIS | Andrew User Interface System [engl.] |
| FUNI | Frame based/Relay User Network Interface |
| WIDL | Web Interface Definition Language |
| IDL | Interface Definition Language |
| IDL | Interface Description Language |
| ISL | Interface Specification Language |
| IDL | Interface/Internet Definition Language |
| OIDL | Object Interface Definition Language |
| NIDL | Network Interface Definition Language |
| I4DL | Interface, Inheritance, Implementation, Installation Definition Language |
| HLLAPI | High Level Language Application Programming Interface |
| UUI | User to User Information |
| UUS | User to User Signalling |
| XQL | XML [eXtensible Markup Language] Query Language |
| EOU | End Of User |
| U | User |
| UEV | User End of Volume |
| UHD | User Help Desk |
| UG | User Group |