| Acronym | Definition |
|---|
| MUD | Multi-User Dungeon (gaming) |
| MUD | Multi-User Dungeon |
| MUD | Municipal Utility District |
| MUD | Moose Utility Division |
| MUD | Make Up Designory (trade school; various locations) |
| MUD | Multi User Adventure |
| MUD | Multi User Dimensions |
| MUD | Multi User Domain |
| MUD | Multi User Detection |
| MUD | Multi User Dungeon |
| MUD | Multi-User Dimension |
| MUD | Matched Unrelated Donor (stem cell transplantation) |
| MUD | Multi-User Domain |
| MUD | Middle Up Down (bridge game) |
| MUD | Metropolitan Utilities District |
| MUD | Multiuser Detection |
| MUD | Manufacturer Usage Description |
| MUD | Master of Urban Design |
| MUD | Multiple User Dialogue |
| MUD | Master Unit Die |
| MUD | Multi-User Detector (communications) |
| MUD | Made Up Drama |
| MUD | Mesa de Unión Democrática (Spanish: Table Democratic Union) |
| MUD | Management of Uncertain Data (workshop) |
| MUD | Modello unico di Dichiarazione Ambiente (Italian: Unique Environment Statement Pattern) |
| MUD | Master User Domain |
| MUD | Marrow Unrelated Donor |
| MUD | Multiple Unit Discount |