Bay windows are perhaps the more common of the two reinforced window styles and generally consist of three windows of varying sizes. The central panel is often the largest, allowing for the best view, and this is then backed up by two panels, known as flankers, that are smaller in size and positioned at an angle.

Unlike bay windows, bow windows can generally consist of anywhere between three and six panels and they are generally all the same size. While the angles used in bay windows are often pronounced, the number of window panels used in bow windows are generally used in order to make for a more curved look.