Moderator: lynn
The term doctor (medical doctor) is older and shorter (see doctor of medicine), but can be confused with holders of other academic doctorates. Doctor (gen.: doctoris) means teacher in Latin and is an agentive noun derived from the verb docere ('teach').
The origins of the doctorate dates back to the ijazat attadris wa 'l-iftta ("license to teach and issue legal opinions") in the medieval Madrasahs from the 9th century, though it was limited to Islamic law at the time, as in a Doctor of Laws degree.
The doctorate was later extended to philosophy in the European universities in the Middle Ages which generally placed all academic disciplines outside the professional fields of theology, medicine and law under the broad heading of "philosophy" (or "natural philosophy" when referring to science).
According to Wellington, Bathmaker, Hung, MucCullough and Sikes (2005), the first Ph.D. degree was awarded in Paris in 1150, but not until the early nineteenth century did the term "Ph.D. degree" acquire its modern meaning as the highest academic doctoral degree, thanks to university practice in Germany. As Wellington et al. explain, prior to the nineteenth century professional doctoral degrees could only be awarded in theology (Th.D.), law (J.D.), or medicine (M.D.).
按：MD在英联邦国家是指医学博士。但是在美国和加拿大，MD却只是医生的合格证书（英联邦的则是MBBS/BMBS等）。The Doctor of Medicine (MD, from the Latin Medicinæ Doctor meaning "Teacher of Medicine") is a doctoral degree for physicians (medical doctors). The degree is granted by medical schools.
It is a first professional degree (qualifying degree) in some countries, including the United States and Canada, although training is entered after obtaining at least 90 hours of university level work (see second entry degree). In other countries, such as United Kingdom and Australia, the MD is a higher doctoral academic research degree resembling a PhD. In Britain and many Commonwealth nations, the qualifying medical degree is instead the Bachelor of Medicine, Bachelor of Surgery (MBBS or BMBS or MBChB).
According to Douglas Guthrie, who bases his account on L Thorndike, medical men were first called "Doctor" at the Medical School of Salerno. He states that the Emperor Frederick II decreed in 1221 that no one should practice medicine until he had been publicly examined and approved by the masters of Salerno. The course lasted 5 years, and to start one had to be 21 years old and show proof of legitimacy and of three years study of logic. The course was followed by a year of supervised practice. After the laureation ceremony the practitioners could call themselves "magister" or "doctor".