Homeworld

The word "homeworld" referred to the planet, or in some cases moon, on which a particular species originated and developed their cultures and their histories on.

For example, Earth was the homeworld of Earth Reptiles, such as Silurians, and humanity, (TV: Doctor Who and the Silurians) and Skaro was the homeworld of the Thals and Kaleds, later the Daleks. (TV: Genesis of the Daleks)

Gallifrey was the homeworld of the Time Lords, (TV: The Time Warrior) and, due to its important role in the Spiral Politic, it was frequently known as simply "the Homeworld". (PROSE: The Book of the War) Residents of the City of the Saved often called it "the Houseworld". (PROSE: Of the City of the Saved...)

The Second Doctor referred to Earth as the mother world in relation to the early colonisation of the solar system. (PROSE: The Wheel of Ice)