Time
- For the entity of the same name, see Time (Eternal).
Time was the continuum/dimension in which one moment progresses to another and through which space-time vessels traveled. The Web of Time governed order within this realm.
Explanations of time
Time has been described as a stream, ever flowing and ever changing. The Vortex had devestating effects on unprotected individuals, only one being is known to have survived exposure to the effects. A Tardis (or other time travel devices) allow one to safely traverse the stream, to go back and forth in time. Time was one of the five dimensions described by Susan Foreman and from which she derived the name TARDIS, which she came up with herself. (DW: An Unearthly Child) While Susan described time as a dimension, the Master (in the guise of "Professor Thascales") described time as made up of particles, known as chronons. (DW: The Time Monster) The Doctor later laboured in an effort to explain how time is misunderstood and never strictly linear, that it is made up of "wibbly-wobbly, timey-wimey... stuff." (DW: Blink)
A certain moment in time could be fixed, where something must happen, such as the volcanic eruption of Mount Vesuvius at Pompeii. (BFA: The Fires of Vulcan, DW: The Fires of Pompeii)
It could also be in flux, allowing minor changes to history. Time isn't in a straight line but is more of a four-dimensional 'circle', and the location where TARDISes travel is the unexplained Time Vortex, which is also used to travel through space as well as time.
Though some events could be changed others were destined to happen, even when a Time Lord utilize his time travel technology to alter the stream certain events rearrange themself to the fixed line, as shown with Adelaide Brooke who commited suicide. Despite the doctor changing her supposed time of death events played out so that they came to pass, one way or another. (Waters of Mars) [source needed]
Though some races have managed to travel through time (such as the Daleks and Time Agency of the 51st century) only the Time Lords were the only species in the universe to have attained Mastery over Time in all it's aspects.