physician [ME] The Old English word for a medical doctor was leech (despite popular belief, nothing to do with the blood-sucking worm, but a word meaning ‘a healer’). Physician arrived in the early Middle Ages, and goes back to Greek phusis ‘nature’, the root also of physical [LME], physics [LME], and numerous other English words. A doctor [ME] was originally not a physician but any learned person able to give an authoritative opinion, especially one of the early Christian theologians. The word started referring specifically to a medical expert at the start of the 15th century. It comes from doctor, the Latin for ‘teacher’, also found in words such as docile [LME] ‘willing to learn’; document [LME] ‘official paper, proof’; and doctrine [LME], originally the action of teaching.