Time window
From Tardis Wiki, the free Doctor Who reference
Time Windows were doorways in time created by pushing energy into Warp drive. The Clockwork Droid's created Time Windows staggered throughout the life of Jeanne-Antoinette Poisson onboard the SS Madame De Pompadour. They were closed when the Doctor broke the link. (DW: The Girl in the Fireplace) In the 21st century, the Shopkeeper, known as Mr. Smalley, could create time-windows. This allowed Sarah Jane, Clyde and Rani, to travel through time.