—Is there a doctor on the plane!?
—Yes, I’m a doctor!
—Oh thank God, come quick, I think he’s having a heart attack!
—Oh, I’m not a medical doctor. I have a PhD in medieval French literature. It’s quite interesting actually. You see…
Why do we use doctor in two such different ways in English? What’s the link between a physician and a top-level academic? Looking at the origin of the word, it comes from the Medieval Latin doctor meaning religious adviser, teacher, or scholar. You can still observe that meaning in modern words such as doctrine or indoctrination. Towards the end of the 16th century, doctor began to replace the much older word leech, meaning physician.
Why this happened isn’t so clear. As in most cases of linguistic drift, it probably happened very slowly over a long period time, without people really noticing. Maybe the ordinary people, without access to much education, didn’t really distinguish between the knowledge of the religious scholar, and the local physician. Both seemed to know so much about the world that they didn’t see much of a difference between them. Now of course, the pendulum has swung the other way almost completely, and when one hears the word doctor, one almost immediately thinks of a medical healer.
What’s curious though, is that this has happened mainly in English. Other modern languages contain words similar to doctor (docteur, dottore, Doktor), but use them mainly to refer to an academic doctor. Instead, they often use words with a more clearly medical origin to refer to physicians (le médecin, il medico, der Arzt). We do have medic as a very broad term for anyone involved in medicine, but it’s not really used often. I think we prefer doctor because it still has some of the prestige of its original Latin, and current academic, meaning. As so often seems to be the case, how a word sounds or its sense of prestige determine how and if we use it.