Tardis

Etymology
From, the designation of the bigger-on-the-inside time machine used in the British science-fiction TV series Doctor Who, said in the 1963 story "An Unearthly Child" to be an abbreviation for "Time And Relative Dimension(s) In Space"..

Proper noun

 * 1)  time machine from the series Doctor Who which is larger on the inside than the outside.

Noun

 * 1) Something which resembles such a machine, either in that it travels through time or in that its interior is or appears to be larger (or more full of information or things) than its exterior suggested.