According to Merriam-Webster dictionary, a surgeon is a medical specialist who practices surgery. Surgery is a branch of medicine that is characterized by invasive medical treatment involving the cutting of a human or an animal body for treating a medical condition such as to repair a breakage or tear or the removal of a diseased organ or tissue such as cancerous tumors or correcting deformities such as a cleft palate. A surgeon can be any of these: a physician, a dentist, a podiatrist or a veterinarian. There are a number of specialties that are recognized within surgery (medicine) including general surgery, cardiothoracic surgery, neurosurgery, oral and maxillofacial surgery, otolaryngology (ENT), pediatric surgery, plastic surgery, trauma and orthopedic surgery, urology, and academic surgery. Some factors are common to all the surgical specialties. For instance, all specialties require some work into teaching, research and management. However, differences also exist between these specialties.