What is the etymology of Doctor Who?

I recently decided to watch Doctor Who, and started viewing the 2005 version. I have the first two episodes from the first season, and I can't help but wonder what is the etymology of the name "Doctor Who"? And why does the protagonist call himself "the Doctor" (or is it "the doctor")?

Answer

In the very first episode of Doctor Who (way back in 1963), the Doctor has a granddaughter going by the name "Susan Foreman", and the junkyard where the TARDIS is has the sign "I.M. Foreman". Barbara, who becomes one of the Doctor's companions, calls him "Doctor Foreman" (probably assuming that is his name given his relationship to Susan), and Ian (another early companion) does the same in the second episode, to which the Doctor says:

Eh? Doctor who? What's he talking about?

"Foreman" is most likely selected as a convenient surname for Susan to use because it happened to be on display near where the TARDIS landed.

Ever since then, there have been a series of "Doctor who?" (as in, "what is his name?") questions by various companions and people that he meets. This is sometimes a serious question, and sometimes a joke, often one made by the Doctor himself. However, he never actually goes by the name "Doctor Who" - it's the title of the series, not the character.

Except that, for the 1st through 4th Doctors, the title credits used the name "Doctor Who" or "Dr Who", even though he was not called this on screen. From the 5th through 8th Doctors, the credit was "The Doctor", then for the 9th Doctor it went back to "Doctor Who". With the 10th and 11th, the credit has gone back to "The Doctor" again.

With the 10th and 11th Doctors, hints have been made about the significance of the Doctor's name:

• Madame de Pompadour says "Doctor who? It's more than just a secret, isn't it?"


• The Carrionite Lilith says "Why would a man hide his title in such despair?"


• Much significance is made of River Song knowing the Doctor's name, with the suggestion that this is part of marriage / a wedding.

It's likely that more will be revealed about this, although it seems unlikely that his name will actually be revealed.

The Doctor has never revealed the origin of the alias "The Doctor", although it's implied that this is a reference to the doctorate ("PhD") type of doctor rather than a medical doctor (i.e. he is a scientist). Explanations as to whether or not he studied to gain this title, and what he studied, and with whom, are varied and inconsistent throughout the history of the show.

The Doctor often uses the name "John Smith" (or even "Doctor John Smith") - this was first used by the 2nd Doctor's companion Jamie McCrimmon, but has been used regularly since then. At the Academy on Gallifrey, he apparently went by "Thete" or "Theta Sigma" (originally revealed in The Armageddon Factor, and confirmed as a nickname in The Happiness Patrol).

Other Time Lords have mocked him for using the title "Doctor". When talking to the Master at the end of The Sound of Drums (a 10th Doctor episode), it is revealed that the Doctor and Master both chose their names: the Master describe's the Doctor's choice:

The man who makes people better. How sanctimonious is that?

However, in The Lodger, the 11th Doctor says:

I'm the Doctor. Well, they call me 'the Doctor', I don't know why; I call me 'the Doctor' too, still don't know why.

Adapted from Wikipedia as well as memory and other sources. The TARDIS Index File has a good summary of the Doctor's aliases.