Jazzo, here's the explanation of the Amish ritual of Meidung from another thread in case you missed it:

http://wordsmith.org/board/showthreaded.pl?Cat=&Board=announcements&Number=71305

Some of the sites said the word is actually a hybrid of German-American (Amish, Pennsylvania Dutch) dialect, but BY indicates it is in use in German proper, though infrequently. Was it originally pure German, BY, or coined by the German-American community here, then making its way back into the native tongue?