It simply means an "in between move"
It inspired a palatable single malt, at least!
I prefer Irish over Scottish. Most Irish pot still whiskey is distilled three times, while most (but not all) Scotch whisky, is distilled twice. Peat is rarely used in the malting process, so that Irish Whiskey has a smoother finish as opposed to the smoky, earthy overtones common to some Scotches.
Here's a game that I played recently in a rated tournament, which features a Zwischenzug (8. Bxc4) right in the opening.
An example of simple zwischwenzug:
White has just pushed c4, setting up a "deadly" fork. but actually Black is doing fine because he can play Rh5+, and then move the other Rook on the next move, avoiding material loss. This is just an example.
read my blog post here to find more advanced examples: http://chesstrainerapp.blogspot.fr/2014/02/zwischenzug-say-it-again.html
25 is not a zwichenzug.