Hi

A jalousie window is a window which is made with a set of movable glass slats, sort of like oversized built-in blinds. When the window is closed, the slats rest against each other, and when the window is opened, the slats separate, permitting plenty of fresh air into the structure. These windows were once extremely common in the American South, when houses could become insufferably hot before the advent of air conditioning.

The earliest reference to jalousies dates back to around the 16th century, and the basic design hasn't changed a lot since, although early jalousie windows were probably made with wooden slats instead of glass ones. The windows are typically manipulated with a crank which moves the housing on either end of the slats, causing them to open up or move down.

Thanks