Original: Though cosmetic or aesthetic surgery is the best-known kind of plastic surgery, most plastic surgery is not cosmetic: plastic surgery includes many types of reconstructive surgery, hand surgery, microsurgery, and the treatment of burns.
Simplified: An example of reconstructive plastic surgery is fixing a part of the body that has been burned. An example of cosmetic plastic surgery is a surgery called a "Face-Lift" (pulling the skin of the face tight so that someone looks younger).