| Abbreviation | Definition |
|---|---|
| MTW | Multiple Toplevel Window |
| MU | Multi User |
| MU | Mysterious Utility |
| MUB | Mandrake User Board |
| MUD | Multi User Dimensional |
| MUD | Multi User Domain |
| MUD | Multi User Dungeon |
| MUFI | Medieval Unicode Font Initiative |
| MUG | Mac User Group |
| MUG | Macintosh Users Group |
| MUG | Microcomputer Users Group |
| MUG | Miser Users Group |
| MUGD | MUMPS User Group Deutchland |
| MUGH | Microsoft User Group Hyderabad |
| MUGI | Microsoft User Group Indonesia |
| MUGM | MidWestern Users Group Meeting |
| MUGP | Macintosh Users Group Portland |
| MUGT | Minolta User Group Thailand |
| MUI | Macromedia User Interface |
| MUI | Magic User Interface |