Also, "minimize" like on Windows is called "Hide" as a general OSX system function. It is command-H, or in the application menu (the menu with the same name as the application). Although games don't necessarily follow the standard functions, so I don't know if it works on Warcraft.
There is also a window-minimize function on the Mac (the yellow button on the upper left of most windows), but that isn't quite what you are looking for, I think.