A physician is a medical doctor, also called MD, or doctor of medicine, that provides healthcare to patients. A physician is not just trained but also licensed as medical practitioner to practice the science and the art of medicine.
A physician can be a primary care provider or a specialist.
Primary care provider: is a physician (M.D. – Medical Doctor or D.O. – Doctor of Osteopathic Medicine), nurse practitioner, clinical nurse specialist or physician assistant, as allowed under state law, who provides, coordinates or helps a patient access a range of health care services.
Specialist: is a doctor or other health care professional who is trained and licensed in a special area of practice. Examples of medical specialists include oncologists (cancer doctor) and hematologists (blood doctor).