A TARDIS (Time and Relative Dimension in Space)is the vehicle used by Time Lords to travel in both time and space. TARDISes are dimensionally transcendental- the inside is bigger than the outside- and are grown, not made, which can take many centuries. A TARDIS can blend into its surroundings using a Chameleon Circuit- although The Doctor’s is broken, forcing the TARDIS to remain disguised as a 1960’s British Police Box.
Also… Sometimes The TARDIS is a woman.
Part of a series on the #Tech of Doctor Who