Time Lord
Time Lords were a species or group of beings who existed in many universes. The Doctor was typically a Time Lord. They were noted for their ability to periodically change their physical form's appearance as a means to evade death.
According to one version of Jenny Nowhere, an infinity of groups of Time Lords, acting as representatives of their universe before the Council of Frogs, wished for their specific realities to be granted a small, memorable number to mark out their importance. Eventually, an “agreement” was reached: one set of Time Lords “got to become the Third Universe in earnest”, but the others “went home believing they'd been the lucky winners”. All the sets of Time Lords, however, were given “a little casket, to be opened only in the gravest of emergency, holding the true knowledge of [their] official number”. This was apparently documented in a book called The Infinity Rassilons, written by Percival Lankin. (PROSE: How To Steal Timeships & To Influence Time Lords)
In one universe, the Thirteenth Doctor described herself as a Time Lord and noted that thanks to being one, she had all the time in the world. (PROSE: Shifting)
The Hitchhiker's Guide To The Multiverse had Circular Gallifreyan on its back-cover. (COMIC: When Casting Calls)
The “[REDACTED] Lords of [REDACTED]” were cited in one of the Crew of the Copper-Colored Cupids' Cupid Fact Files as one of the authorities with multiversal powers who did not look kindly upon would-be interdimensional conquerors. (PROSE: The Crew of the Copper-Colored Cupids)
In one universe, the Eleventh Doctor described himself as a Time Lord “from the planet Gallifrey in the constellation of Kasterborous” to Wednesday Addams. (PROSE: Wednesday and the Doctor)
In the 89067986779811167562948736197891674912223184th Universe, which was very similar to the Third Universe, Time Lords lived on Gallifrey and studied at the Academy. Andro and Fabian were two “fully-qualified” Time Lords who worked in the Old Workshops watching over the docking bays of damaged TARDISes; neither was on his first life. Young Time Lords could also fast-track through the Academy to become Junior Time Technicians who would be able to work directly with TARDISes much sooner, albeit in a subaltern capacity. When he first met her, the First Doctor initially wondered if Jenny Nowhere was a fellow Time Lord, perhaps an old friend in a new body, but was puzzled at her lack of “House or Chapter identification of any kind”. (PROSE: How To Steal Timeships & To Influence Time Lords)
Jenny Everywhere was familiar with "magic men" and their dwellings that were more impressive on the inside than their outsides betrayed. When arriving at Willy McDuff's "chocolate factory", she hoped McDuff would be like them as she saw that the exterior was a mere werehouse. Appearances weren't deceiving. (PROSE: A World of Pure Unimagination)
Other uses of the term
Lord Thymon, an eldritch abomination who was a literal Embodiment of time in the Void, was once described as a “Time Lord” by the Book of Evil, although this was presumably just a turn of phrase. (PROSE: The Book of Evil)
