Arthur, William (1857) An Etymological Dictionary of Family and Christian Names. New York: Sheldon, Blakeman. Public Domain.
DUN
As described in historical dictionaries
An Etymological Dictionary of Family and Christian Names (1857)
(origin: Local) From the parish of Dun, Forfarshire, Scotland, derived from the Gaelic Dun, a hill or rising ground, a fort or castle.
Origin: Celtic
Region of origin: British Isles
Country of origin: Scotland
Religion of origin: Christian
Language of origin: Gaelic