Hyperspace
Hyperspace was a dimension distinct from normal space, where one could travel faster than 180,000 miles per second and avoid the time distortion effect stated in Einstein's Theory of relativity. According to the Fourth Doctor, it was an absurdity — it was only supposed to be a theory. Romana I agreed with this. On Gallifrey, hyperspace was barely touched upon. (TV: The Stones of Blood) In the days before the Thousand Year War, the planet Skaro was located deep in Hyperspace, (COMIC: Genesis of Evil) and a stranded Dalek was once found in "the little-known depths of hyperspace" by a human expedition. (PROSE: Doctor Who and the Daleks)
Hyperspace was a subset of the Time Vortex, (PROSE: The Crystal Bucephalus) and one account referred to the "vortex" of hyperspace; it may have been the core of the Time Vortex. (PROSE: State of Change)
The Nimon opened gateways into hyperspace using black hole based transmats, channelling an energy beam through the opening for motive power for their transmat capsules. The Nimon referred to this as the "Great Journey of Life". (TV: The Horns of Nimon)
Hyperspace allowed ships to travel great distances while in another type of space which allowed for an alternative to faster than light drives. The ships would disappear from normal space, enter hyperspace and return. (TV: Nightmare of Eden) These hyperspace vessels used a form of warp drive to travel into this dimension. (PROSE: Doctor Who and the Nightmare of Eden).
Icarons could be used to allow a ship make the transition between normal space and hyperspace. (PROSE: Original Sin)
Hyperspace permitted communication over great distances. Through use of an ionic vibrator, Prentice, her mind in shock from a fall, was able to hear the voice of Zex, even though he was five hundred light-years away. The Master used the same device to send his thoughts into hyperspace and contact Zex. (PROSE: Listen - The Stars) In the 100th century, androids communicated through webwork transmissions via hyperspace. (PROSE: The Crystal Bucephalus)
Both the Grold and the Semquess had ships which could travel in hyperspace. (PROSE: The Eye of the Giant)
The Third Doctor once materialised in front of a ship, forcing it to pull out of hyperspace. (TV: Frontier in Space)
By the 25th century, humans had the ability to travel in hyperspace and such journeys had become commonplace and commercial. (PROSE: Judgement of the Judoon)
A space-faring version of the Orient Express travelled through space along hyperspace ribbons. (TV: Mummy on the Orient Express)
By 2815, a section of hyperspace was being used as a short-cut for various ships. The Cerberus ship caused a huge traffic jam when it attempted to escape the hyperspace tunnel as it was closing. The ship was eventually found by the authorities, but it was deserted, leading to it being called the "Mystery of the Cerberus". By 3012, it, along with the prison ship the Montressor which had crashed into it, became a space station called the G-Lock, where the Festival of Death took place. (PROSE: Festival of Death)
When travelling from 1138 Essex to Skaro, Colony Sarff travelled with their prisoners the Twelfth Doctor, Missy and Clara Oswald in their spaceship via hyperspace. (TV: The Magician's Apprentice)
The battle between Qataka's spacecraft and Utnapishtim's space ark was one of manoeuvres into and out of hyperspace. (PROSE: Timewyrm: Genesys)
Poseidon was tethered to a hyperspace corridor, one that both prevented it from falling into the gravity well of Hades' Helix and allowed them to beam their collected energy to Ultima Tarsus. When the station collapsed, the Tenth Doctor evacuated the crew via the hyperspace corridor. (COMIC: The Lost Dimension)
During the Last Great Time War, Mo and Rondig attempted to escape the Daleks via a hyperspace jump only for the Daleks to strike their craft as their drive activated, forcing them back into realspace. (AUDIO: Saviour)