Time loop

A time loop, known technically as a chronic hysteresis is a loop in time, in which the individuals are always experiencing the same events in an endless loop.

The Third Doctor attempted to explain the concept to the Brigadier and Jo Grant as a "loop in time". (DW: The Claws of Axos).

Notable uses of time loops

 * Several planets were placed into time loops by the Time Lords, including the War Planet and the Fifth Planet. (DW: The War Games, NA: Timewyrm: Exodus, DW: Image of the Fendahl, EDA: The Taking of Planet 5)
 * Axos was placed into a time loop. (DW: The Claws of Axos)
 * While the completed Key to Time would have stopped time altogether, five pieces and a makeshift sixth made of chronodyne was enough to generate a temporary time loop. (DW: The Armageddon Factor)
 * Meglos used a time loop to trap the Doctor and Romana in the TARDIS to prevent them reaching Tigella.
 * Captain Jack Harkness was trapped in a time loop with his fellow renegade Time Agent, Captain John for five years. (TW: Kiss Kiss, Bang Bang)