The title pretty much says it all. I see in this article an in-universe explanation, but I'm thinking more out of universe, from an original writing and production point of view.

Any Whovian can tell you TARDIS stands for "Time And Relative Dimension In Space". Did it start out meaning that though, or did they go back later and say "Hey, we should make the name stand for something?"

  • I would say it was named differently, but it was renamed TARDIS by altering the Timeline, so the answer depend if you talk in relative or absolute time.
    – DavRob60
    Jun 7, 2012 at 16:21
  • TARDIS is defintely an acronym (Susan claimed to have created it, and how is explained at one point in Lungbarrow). But, the expansion of SIDRAT was a backronym. Nov 7, 2015 at 21:04

4 Answers 4


If it's a backronym, it was constructed as such before the show began. "An Unearthly Child" is the very first episode, and has this dialogue:

SUSAN: The TARDIS can go anywhere.

BARBARA: TARDIS? I don't understand you, Susan.

SUSAN: Well, I made up the name TARDIS from the initials. Time And Relative Dimension In Space. I’d thought you both would understand when you saw the different dimensions inside from those outside.

  • Ah, yeah... I saw that bit, but didn't catch that that episode was the original very first. Guess you can't go much further back.
    – eidylon
    Jun 7, 2012 at 17:07
  • 6
    It's a bit hard to reconcile Susan's claim that she made up the name with the near-universal use of the name by other Time Lords and advanced races but eithee way, there's no evidence that the word was ever anything but an acronym with its current meaning.
    – KutuluMike
    Jun 7, 2012 at 18:23
  • 2
    Then again, she IS a time traveler; she could have made the name up and then gone back in time to put it in general use by all.
    – eidylon
    Jun 7, 2012 at 18:45

Given that the name TARDIS and it's meaning is presented in the very first Doctor Who episode, back in the sixties, an the expanded name sounds really constructed just to make up something you can pronounce, I'd assume you can say it's an acronym. They probably sat around thinking: Hey we need a cool sounding name but it should also mean something.

  • 2
    That would still make it an acronym. To be a backronym, the word has to be already in use before you start considering phrases. Thinking about both possible phrases and the words they form is the way acronyms are normally constructed.
    – cjm
    Jun 7, 2012 at 17:50

TARDIS was created by the BBC from the Latin word ASTRID or "Divine Strength". When they decided upon a name they liked, they had to find words that fit it. Therefore, Tardis in real life is a backronym but in-universe it's an acronym.

  • 3
    Where did you hear this? Do you have a source you can share? Nov 8, 2015 at 3:28
  • Agree with Jason; this is an interesting bit of history... wonder where the backstory of this comes from.
    – eidylon
    Nov 8, 2015 at 3:30
  • No actual online reference. Astrid Peth was the woman Ten fell in love with and now lives as intelligent plasma, travelling the universe. Self admittedly her name was chosen because it is an anagram of Tardis. It doesn't take much to realize that the name Tardis was originally designed as an anagram of Astrid. Why nobody bothered to write that down or admit it, I don't know.
    – Eric
    Nov 9, 2015 at 13:46

In series 9 episode 8 (The Zygon Inversion), the following exchange takes place:

DOCTOR: The Tardis.
OSGOOD: What does it stand for?
DOCTOR: What? You're kidding me? Surely you know that?
OSGOOD: Well, I've heard a couple of different versions.
DOCTOR: I made it up from the initials. It stands for Totally And Radically Driving In Space.

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