TARDIS is short for
Time and Relative
Dimensions in
Space, it is a mode of
transport used by the
Time Lords of
Gallifray and capable of transport anywhere and
anywhen in the
universe (or even outside it). These devices are larger on the inside then the outside (thanks to
dimensional engineering) and capable of changing their outer appearance to
blend in with the surroundings of their destination.
The Doctor (see
Doctor Who) stole a
Type 40 TARDIS from his people and took off round the universe, soon after leaving the
chameleon circuit got stuck and the TARDIS was no longer able to change its appearance from that of a 1970s type
British police telephone box.
In a
BBC book, the Doctor's original TARDIS was destroyed and one of his
companions mutated in to a new one. Being the most advanced TARDIS in the universe she and the Doctor have to flee from the
Time Lords who want to capture her and mate her with their bull TARDIS's to form a new race of
time machines to help them in their war with
The People.