orthopedics (also orthopaedics): The branch of medicine that deals with the prevention or correction of injuries or disorders of the skeletal system and associated muscles, joints, and ligaments.
Basically a bone & joint doctor, depending on the specialty (or lack thereof) deals with broken arms, injuries of the spine, arthroscopy, osteoporosis, joint replacements, crushed hands... lots of casts and pins and rods and plates. My dad's an orthopedic surgeon. I think it's amazing to watch. He's described it as carpentry, but with bones instead of wood.