DACH would be: (D)eutschland (A)ustria (C)onfederatio (H)elvetica...
This acronym manages to use three different languages, german for Deutschland, english for Austria (which is Österreich) and the latin name for Switzerland...
Don't ask me, it is very dubious to use this DACH hodgepodge term here, as definitely mentalities are different: the state of IT is in no way identical between these three countries.
Also, Dach stands for "roof" in German, I guess that's why they like it. maybe