The word "Homeworld" referred to the planet, or in some cases moon, on which a particular species originated. For example, Earth was the homeworld of Earth Reptiles, such as Silurians, and humanity. (DW: Doctor Who and the Silurians) Gallifrey was the homeworld of the Time Lords, (DW: The Time Warrior) and Skaro was the homeworld of the the Thals and Kaleds, later Daleks. (DW: Genesis of the Daleks)
