In the Bon religion dMu are one of the eight types of country gods. They are bloated fiends, dark purple in color. The Bon religion still has some followers in parts of Tibet, but they are slowly being converted to Buddhism.
Also, (DMU) Diesel Multiple-Unit train. This is a diesel train in which each passenger carriage has it's own engine. This is an efficient way for engine power to be matched with the changes in demand as the train changes length.
And DMU also stands for Data Manipulation Unit.