Bay Window
A bay window is made up of three or more windows. The side or flanker units project out from the building in 30, 45, or 90 degree angles. The center is parallel with the building wall and is made up of one or more windows. All the units can be stationary, operating or any combination thereof. These types of windows can be installed with head and seat boards.
Bow Window
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.