A time jump was a temporal discontinuity or a mode of time travel. It was "smoother" than travel using a vortex manipulator. (AUDIO: I Went to a Marvellous Party)
Fenris used a time-jumper to travel back to the early days of Gallifreyan history, charged with averting the dawn of the Time Lord civilisation. His attempt was foiled by Rassilon, who eventually took from the time-jumper the directional control device, a piece of technology still missing from the Gallifreyan time travel technology. (COMIC: Star Death)
The Justinian was sent via a time jump from 26th century Ordifica to the late 18th century Anathema. (PROSE: Interference - Book Two)
The Handbots at the Two Streams Facility on Apalapucia could jump between time streams , though they didn't teleport (despite the appearance of the time jump). (TV: The Girl Who Waited)