{{Infobox fictional artifact | name = TARDIS | image = Tardis BBC Television Center.jpg | caption = TARDIS prop used between 2010 and 2017 | source = Doctor Who | source_type = TV | company = BBC | first = An Unearthly Child (1963)' | creator = | genre = Science fiction | type = Time machine/spacecraft | uses = Travels through time and space | traits = Can change its outer dimensions and inner layout, impregnable, telepathic | affiliation = }} The TARDIS (; acronym for "Time And Relative Dimension(s) In Space") is a fictional hybrid of the time machine and spacecraft that appears in the British science fiction television series Doctor Who and its various spin-offs. Its exterior appearance mimics a police box, an obsolete type of telephone kiosk that was once commonly seen on streets in Britain. Paradoxically, its interior is shown as being much larger than its exterior, commonly described as being "bigger on the inside". Due to the significance of Doctor Who in popular British culture, the shape of the police box is now more strongly associated with the TARDIS than its real-world inspiration. The name and design of the TARDIS is a registered trademark of the British Broadcasting Corporation (BBC), despite the fact that the design was originally created by the Metropolitan Police Service. Name TARDIS is an acronym of "Time And Relative Dimension(s) in Space". The word "Dimension" is alternatively rendered in the plural. The acronym was explained in the first episode of the show, An Unearthly Child (1963), in which the Doctor's granddaughter claims to have made it up herself. Generally, "TARDIS" is written in all uppercase letters, but may also be written in title case as "Tardis". The word "Tardis" first appeared in print in the Christmas 1963 edition of Radio Times, which refers to "the space-time ship Tardis", and this publication has often italicised it to connote a ship's name. Description In the fictional universe of the Doctor Who television show, TARDISes are space and time-travel vehicles of the Time Lords, beings from the planet Gallifrey. Although many TARDISes exist and are sometimes seen on-screen, the television show mainly features a single TARDIS used by the show's protagonist, a Time Lord who goes by the name of the Doctor. TARDISes are built with a "chameleon circuit", a type of camouflage technology that changes the exterior form of the ship to