Spatio-temporal hyperlink

A spatio-temporal hyperlink was what the Tenth Doctor called a connection between the SS Madame de Pompadour in the 51st century and 18th century France. He said he had "no idea" what the phrase actually meant as he "[j]ust made it up" on the spot; he "[d]idn't want to say 'magic door'." It had been established by the Clockwork Droids in their quest for "spare parts" — specifically, the brain of Reinette. (TV: The Girl in the Fireplace)