Anesthesiologist: A physician or, less often, a dentist who is specialized in the practice of anesthesiology, the branch of medicine involving the use of drugs or other agents that cause insensibility to pain.

There is a major distinction between an anesthesiologist and an anesthetist. An anesthesiologist has a doctorate whereas an anesthetist does not. An anesthetist is a nurse or technician trained to administer anesthetics.