Space

From Tardis Wiki, the free Doctor Who reference

Space was a word used to refer to two different concepts relating to the universe. One referred to dimensions; space was linked to time, with space being three dimension and time the fourth. (TV: An Unearthly Child) 'Space' was also defined as the vacuum in the universe, outside of a planetary body's atmosphere. This was often known as "outer space." (TV: The Runaway Bride)

See also

Space