What is "arnor"

Arnor is a fictional kingdom in J. R. R. Tolkien's writings. Arnor, or the Northern Kingdom, was a kingdom of the Dúnedain in the land of Eriador in Middle Earth. The name probably means "Land of the King", from Sindarin Ara- (high, kingly) + (n)dor (land). Arnor is the territory of Middle-earth associated with the High Kings of the line of Elendil, the kingship of which was restored at the crowning of Elessar ( Aragorn) after the War of the Ring at the start of the Fourth Age.

At its greatest, Arnor encompassed almost the whole region of Eriador between Bruinen, Gwathló and Lhûn, and the region which would later be known as the Shire. Arnor's population included Dúnedain in western-central regions and mixed or indigenous peoples. The first capital was Annúminas near Lake Nenuial; the capital was moved to Fornost sometime after the division of the kingdom.