word of the week: CHICAGO WINDOW
CHICAGO WINDOW: A window occupying the full width of a bay, and consisting of one large fixed center panel flanked by two smaller double hung sash windows.
The Chicago Window was an important development for commercial architecture at the turn of the twentieth century. This was a time when electricity was limited and air conditioning non-existent. The great expanse of the Chicago Window provided natural light, and the sash windows (which could open and close) provided ventilation.