The TARDIS(/ˈtɑrdɪs/; Time And Relative Dimension In Space) is a time machine and spacecraft in the British science fiction television programme Doctor Who and its associated spin-offs The Sarah Jane Adventures,
Torchwood and more.
A TARDIS is a product of the advanced technology of the Time Lords, an extraterrestrial civilisation to which the
programme's central character, the Doctor, belongs. A properly maintained and piloted TARDIS can transport its occupants to any point in time and space. The interior of a TARDIS is much larger than its exterior. It can blend in with its surroundings using the ship's "
chameleon circuit". TARDISes also possess a degree of
sapience (which has been expressed in a variety of ways ranging from implied machine personality and free will through to the use of a conversant avatar) and provide their users with additional tools and abilities including a telepathically based universal translation system.
In the series, the Doctor pilots an apparently unreliable, obsolete Type 40, Mark 1 TARDIS. Its chameleon circuit is broken, leaving it stuck in the shape of a 1960s-style
London police box after a visit to London in 1963. The Doctor's TARDIS was for most of the series' history said to have been stolen from the Time Lords' home planet,
Gallifrey, where it was old, decommissioned and derelict.