A series of four or more adjoining window units, commonly five in number, installed on a radius from the wall of the building. These types of windows can be installed with head and seat boards.
Bow windows are window units made up of 4 to 6 windows in a graceful arc shape with a shallow insulated seat.
Bow windows typically have fixed center windows with operating casements on the ends.
You may be able to upgrade an existing window opening to a bow.