A Guide to Classic Who references in New Who and the Doctor.
The Doctor, obviously, isn't a name but rather a title. So what his the Doctor's name? We just don't know.
Even when on trial (like the Second Doctor story "The War Games" or the Sixth Doctor story "Trial of the Timelord") by his own people they called him The Doctor (although many of Timelords go only by a just a title, not a name). He has been called "Theta Sigma" or "Thete" by some, but that is claimed to be his nickname from the Time Lord Academy, not his actual name.
Because his granddaughter went by the name Susan Foreman, in the show's second episode Ian refers to him as "Doctor Foreman" to which the Doctor replies "Doctor Who? What is he talking about?"
“WHO IS DOCTOR WHO”
The name of the show and, as such, many people refer to the character by that name. There have only been a few references in-story, though.
- In the First Doctor story "The War Machines" the computer WOTAN referred to him as "Doctor Who"
- The Second Doctor signed a message once as "Dr W."
- The Second Doctor used the alias "Doctor von Wer" (Doctor [of] Who.)
- The Third Doctor was called "the great wizard Quiquaequod" (Who in different Latin variations.)
Some of the other material states that his real name is unpronounceable by humans.
BEHIND THE SCENES
The original idea for the series "Dr Who" had the main character an amnesiac from the future and the three modern humans who travel with him call "Dr Who" since not even he remembers his name.
This idea was dropped when the idea was reworked, but stuck with the production team, appearing in credits, episodes titles and promotional material as the character's name.
Some fans see using the term "Doctor Who" as the Doctor's name is a mistake made by the uninitiated, like calling the Monster in Mary Shelley's novel "Frankenstein". Others, say that the minor references make it OK. It's one of those things that cause nerd fights so be careful using it.