The name "ball gown wedding dress" is self-explanatory. If you have absolutely no clue, think of what Cinderella wore to the ball. Some people called it the "fairy-tale" style.
The silhouette of ball gown wedding dress and princess wedding dress can be quite similar, especially when the princess wedding dress is boosted by the petticoat hoop. The main difference lies in way the seams run. Ball gown wedding dresses have horizontal seam at the waistline where the skirt starts to grow fuller.
Ball gown wedding dresses are usually paired with fitted bodice line. They look fabulous on brides with slim waistline and is perfect for hiding full hips - good disguise for pear body shape. Note that brides with large body frame should think twice about this style as it may make them look bigger. On the other hand, very petite brides may also find it overwhelming to carry too much extra fabric for their small frame.