What name did J.R.R. Tolkien give the central continent of his invented world?

J.R.R. Tolkien called the central continent of his invented world Middle-earth. The term describes the primary setting of The Hobbit and The Lord of the Rings.

Middle-earth is not the entire universe of Tolkien’s mythology. It is part of Arda, the world created in Tolkien’s fictional history. Other important regions include Aman, the land to the west across the sea, and Númenor, an island kingdom that was later destroyed.

The name is Tolkien’s modern English rendering of an old Germanic concept for the inhabited world between heaven and the underworld. It is related to the Old English word middangeard and does not simply mean a planet located inside Earth.

The geography and history of Middle-earth extend across many ages. The Lord of the Rings takes place near the end of the Third Age, while much of The Silmarillion concerns earlier periods.