Earth

From Srafopedia

The Earth is the name, in English, given to what we now know to be the third planet from the Sun. In Our World and Lyra's World it is the World of Mankind, and is considered, in some religions, to be separate from Heaven -- the World of gods, spirits, angels -- and Hell.

All Other Worlds in His Dark Materials are parallel versions of The Earth, existing in different universes of the Multiverse.