The Uncle

 was a Time Lord from Gallifrey and an uncle of the Doctor. (GAME: The Eternity Clock)

While his mind was within the time brain, the Seventh Doctor, in response to Albert Einstein's statement, "It is a fundamental postulate that all motion is relative", told him that he would not say that if he had met the Doctor's uncle. (TV: Time and the Rani)

On one occasion, River Song used the British idiom "Bob's your uncle" in front of the Eleventh Doctor, who retorted that his uncle was not called Bob, but "the Uncle." When River expressed skepticism about the existence of such a name, the Doctor described it as "a Time Lord thing." (GAME: The Eternity Clock)

When Caitlin asked the Doctor if he was like Harry Potter due to him being able to speak to the snakes, The Doctor said that he was not like Harry Potter, but he did get locked in a cupboard under the stairs "when I was your age by my uncle". (PROSE: Horror Of The Space Snakes)