The world, the earth, regarded as a middle region between heaven and hell, or as occupying the centre of the universe. Sometimes also: the inhabitants or things of the world, especially as opposed to those of heaven; worldly things as opposed to divine or spiritual things. In later use chiefly archaic or literary. Compare "middenerd", "middle-erd", mid-earth .
In modern use frequently with reference to the fiction of J. R. R. Tolkien or to other fantasy literature; compare.
Middle English; earliest use found in Layamon (fl. 1250), poet. From middle + earth.