A doctor of medicine or osteopathy who is authorized to practice medicine or surgery by the state where they practice. The definition also includes: podiatrists, dentists, clinical psychologists, optometrists, chiropractors (related to spinal manipulation), nurse practitioners, nurse-midwives, clinical social workers, physician assistants, and listed Christian Science practitioners. These professionals, including health care providers practicing in a country other than the United States, must be authorized to practice in that state/country and must be performing within the scope of their practice as defined under state law.