The Dúnedain (singular: Dúnadan) were the Men who descended from the Númenóreans who survived the fall of their island kingdom and came to Eriador in Middle-earth led by Elendil and his sons. They are also called the Men of the West and the Men of Westernesse (direct translations of the Sindarin term). They settled mainly in Arnor and Gondor.
After the fall of Arnor and then Arthedain, some of the northern Dúnedain became the Rangers of the North. The surviving Dúnedain population of Arnor retreated to the Angle south of Rivendell. In the mean time the southern Dúnedain intermarried more and more with so-called Middle Men, except in some regions (such as Dol Amroth).
The Westron name for Dúnadan was simply Adûn, "westerner", but this name was seldom used.
This name was reserved to those Númenóreans who were friendly to the Elves: the other, hostile survivors of the Downfall were known as the Black Númenóreans.