Mordor and the Shire are regions of J.R.R. Tolkien’s fictional world of Middle-earth.
Middle-earth is the setting for The Hobbit, The Lord of the Rings, and much of Tolkien’s legendarium. It includes many peoples and territories, among them the Shire, Rohan, Gondor, Rivendell, and Mordor. The One Ring’s central conflict moves across this landscape from the peaceful Shire to Sauron’s realm in the east.
The name does not simply mean a planet separate from Earth. Tolkien used “Middle-earth” as a modern rendering of an older Germanic and English idea for the inhabited world between cosmic realms. In his mythology, it is part of Arda, the larger world created by the divine powers called the Valar.
Readers sometimes use Middle-earth to mean the entire Tolkien universe, but it is more precisely a particular region or historical world within that mythology.