"Ortho" means straight, and "gnathic" means jaw. Together, orthognathic surgery refers to “straightening” of the jaws, ie correcting any “crookedness” or deformity of the jaws. "Plastic", refers to changing or moulding shape, and plastic surgery then refers to surgery that changes the shape or form. It can be further subdivided into aesthetic plastic surgery, where the objective is primarily improving the cosmesis of a body structure which is not diseased, and reconstructive plastic surgery, which as the name suggests, rebuilds diseased or defective body parts. So, in the strict sense of the word, orthognathic surgery is a form of reconstructive plastic surgery. However, it is not aesthetic plastic surgery, which is the plastic surgery that most people know of.