A physician — also known as medical practitioner, doctor of medicine, medical doctor, or simply doctor — practices the ancient profession of medicine, which is concerned with maintaining or restoring human health through the study, diagnosis, and treatment of disease or injury. This properly requires both a detailed knowledge of the academic disciplines (such as anatomy and physiology) underlying diseases and their treatment — the science of medicine — and also a decent competence in its applied practice — the art or craft of medicine. Both the role of the physician and the meaning of the word itself vary significantly around the world, but as generally understood, the ethics of medicine require that physicians show consideration, compassion and benevolence for their patients. The word physician comes from the Ancient Greek word φύσις (physis) and its derived adjective physikos, meaning "nature" and "natural". From this, amongst other derivatives came the Vulgar Latin physicus, which meant a medical practitioner. After the Norman Conquest, the word entered Middle English, via Old French fisicien, as early as 1100. Originally, physician meant a practitioner of physic (pronounced with a hard C). This archaic noun had entered Middle English by 1300 (via Old French fisique). Physic meant the art or science of treatment with drugs or medications (as opposed to surgery), and was later used both as a verb and also to describe the medications themselves.[2][3][4] In English, there have been many synonyms for physician, both old and new, with some semantic variation. The noun phrase medical practitioner is perhaps the most widely understood and neutral synonym. Medical practitioner is lengthy but inclusive: it covers both medical specialists and general practitioners (family physicians, family practitioners), and historically would include physicians (in the narrow sense), surgeons and apothecaries. In England, apothecaries historically included those who now would be called general practitioners and pharmacists. The term doctor (medical doctor) is older and shorter, but can be confused with holders of other academic doctorates (see doctor of medicine). Doctor (gen.: doctoris) means teacher in Latin and is an agent noun derived from the verb docere ('teach').[5] A cognate expression occurs in French as docteur médecin , a direct equivalent of medical doctor or doctor of medicine, and commonly found as its contraction, médecin (doctor, physician). The Greek word ἰατρός (iatrós, doctor or healer) is often translated as physician. Ἱατρός is not preserved directly in English, but occurs in such formations as psychiatrist (translates from Greek as healer of the soul), podiatrist (foot healer), and iatrogenic disease (a disease caused by medical treatment). In Latin, the word medicus meant much what physician or doctor does now. Compare these translations of a well-known proverb (the nouns are in vocative case): The ancient Romans also had the word archiater, for court physician. Archiater derives from the ancient Greek ἀρχιατρός (from ἄρχω + ἰατρός, chief healer). By contraction, this title has given modern German its word for physician: arzt. Leech and leechcraft are archaic English words respectively for doctor and medicine.[2] The Old English word for "physician", læċe, which is related to Old High German lāhhi and Old Irish liaig, lives on as the modern English word leech, as these particular creatures were formerly much used by the medical profession. Cognate forms for leech exist in Scandinavian languages: in modern Swedish as läkare, in Danish as læge, in modern Norwegian as lege (bokmål) or lækjar (nynorsk), and in Finnish as lääkäri. These Scandinavian words still translate as doctor or physician rather than as a blood-sucking parasite. In modern English, the term physician is used in two main ways, with relatively broad and narrow meanings respectively. This is the result of history and is often confusing. These meanings and variations are explained below. Especially in North America, the title physician is now widely used in the broad sense, and applies to any medical practitioner holding a medical degree. In the United States and Canada, the term physician usually describes all those holding the degrees of Doctor of Medicine (MD) and Doctor of Osteopathic Medicine (DO). Within North America, the title physician, in this broad sense, also describes the holders of medical degrees from other countries that are equivalent to the North American Doctor of Medicine degrees; typical examples of such degrees from Commonwealth countries are MB BS, MB BChir etc. In the USA, only those graduating from faculties listed in the WHO Directory of Medical Schools [6] are able to apply for medical licensure in the relevant US jurisdiction, via the ECFMG.[7] The American Medical Association, established in 1847, currently uses physician in this broad sense to describe all its members. However, the American College of Physicians, established in 1915, does not: its title uses physician in an older, narrower sense, as discussed below. Physician is still widely used in its older, more narrow sense, especially outside North America. In this usage, a physician is a specialist in internal medicine or one of its many sub-specialties (especially as opposed to a specialist in surgery). This traditional meaning of physician conveys a sense of expertise in treatment by drugs or medications, rather than by the procedures of surgeons.[8] This older usage is at least six hundred years old in English: physicians and surgeons were once members of separate professions, and traditionally were rivals. The Shorter Oxford English Dictionary, third edition, gives a Middle English quotation making this contrast, from as early as 1400: Henry VIII granted a charter to the London Royal College of Physicians in 1518. It wasn't until 1540 that he granted the Company of Barber/Surgeons (ancestor of the Royal College of Surgeons) its separate charter. In the same year, the English monarch established the Regius Professorship of Physic at the University of Cambridge.[9] Newer universities would probably describe such an academic as a professor of internal medicine. Hence, in the 16th century, physic meant roughly what internal medicine does now. Currently, a specialist physician in this older, narrower sense would probably be described in the United States as an internist. Another term, hospitalist, was introduced in 1996,[10] to describe US specialists in internal medicine who work largely or exclusively in hospitals. Such 'hospitalists' now make up about 19% of all US general internists,[11] who are often called general physicians in Commonwealth countries. The older, more narrow usage of physician as an internist is common in the United Kingdom and other Commonwealth countries (such as Australia, Bangladesh, India, New Zealand, Pakistan, South Africa, Sri Lanka, Zimbabwe), as well as in places as diverse as Brazil, Hong Kong, Indonesia, Japan, Ireland, and Taiwan. In such places, the more general English terms doctor or medical practitioner are prevalent, describing any practitioner of medicine (whom an American would likely call a physician, in the newer, broad sense).[12] In Commonwealth countries, specialist pediatricians and geriatricians are also described as specialist physicians who have sub-specialized by age of patient rather than by organ system. Around the world, the combined term "Physician and Surgeon" is a venerable way to describe either a general practitioner, or else any medical practitioner irrespective of specialty.[2][8] This usage still shows the older, narrower meaning of physician and preserves the old difference between a physician, as a practitioner of physic, and a surgeon. The term may be used by state medical boards in the United States of America, and by equivalent bodies in provinces of Canada, to describe any medical practitioner. Osteopaths are recognized as physicians in 48 countries, particularly in the USA (where they are no longer called osteopaths, but osteopathic physicians or just physicians), where they have unlimited practicing rights in all specialties and subspecialties of medicine. In the USA, osteopathic medical schools (DO) have a curriculum almost identical to allopathic (MD) schools with the exception of osteopathic manipulative medicine, which focuses on extra instruction in the musculoskeletal system. Internationally, there are variations in the DO degree; osteopathic education includes teaching manipulative medicine.[13] In the majority of US states, the term "physician" has either been legislated or determined by the Courts to include holders of the Doctor of Chiropractic[14] (DC) degree (the US Federal Code states that any doctor treating MediCare patients is a "physician" ). In a few jurisdictions, "physician" may also refer to a holder of the Doctor of Naturopathic Medicine (ND) degree.[15] Within the USA, podiatrists have a Doctor of Podiatric Medicine degree (DPM) and may be described as podiatric physicians; in most hospitals, podiatrists typically fall under the Department of Surgery.[16] Nurse practitioners (NPs) are not described as physicians; the American College of Nurse Practitioners do not describe themselves this way. They are classified as advance practice registered nurses/clinicians, and are also known as mid-level (healthcare) practitioners in US government regulations.[17] Nurse practitioners may perform work similar to that of physicians, especially within the realm of primary care, but use advanced nursing models instead of medical models. The scope of practice for a Nurse Practitioner in the United States is defined by individual state boards of registration in nursing, as opposed to state boards of registration in medicine. Physician Assistants are also classified as midlevel advance practice clinicians, have a similar scope of practice as nurse practitoners, and are regulated by state boards of registration in medicine. Within Western culture and over recent centuries, conventional Western medicine has become increasingly based on scientific reductionism and materialism. This style of medicine is now dominant throughout the industrialized world, and is often termed Biomedicine by medical anthropologists.[18] Biomedicine "formulates the human body and disease in a culturally distinctive pattern",[19] and is a world view learnt by medical students. Within this tradition, the medical model is a term for the complete "set of procedures in which all doctors are trained" (R. D. Laing, 1972),[20] including mental attitudes. A particularly clear expression of this world view, currently dominant among conventional physicians, is evidence-based medicine. Within conventional Western medicine, most physicians still pay heed to their ancient traditions: