Galactic centre

From TARDIS Index File, the free Doctor Who reference.

Galactic Centre was a point used to measure in relation to other planets and locations. It was used as a starting point for galactic coordinates, for example. Gallifrey was, for example, located at 10-0-11-0-0 by 0-2 from galactic zero centre. (DW: Pyramids of Mars)

The Galactic Centre was also the centre of power for Human affairs during the time of Helen A's rule on Terra Alpha. (DW: The Happiness Patrol)