Dreh-Kipp Windows
Windows with two opening and closing functions, one of which involves rotating inwards horizontally (“collapsing inwards”), while the other operates by rotating inwards vertically (“opening inwards”), are called Dreh-Kipp (turning, tilting) windows. Such windows first emerged in Germany: the term Dreh-Kipp consists of the German words drehen (to turn) and kippen (to tilt).