Arthur, William (1857) An Etymological Dictionary of Family and Christian Names. New York: Sheldon, Blakeman. Public Domain.
DUNLOP
As described in historical dictionaries
An Etymological Dictionary of Family and Christian Names (1857)
(origin: Gaelic. Local) A parish in the district of Cunningham, Ayrshire, Scotland; from Dun, a castle, fort, or hill, and lub, a curvature, a bending of the shore--the castle or hill at the bend.
Patronymica Britannica (1860)
DUNLOP. (Often corrupted in Scotland to Dunlap and Delap.) Traced to the year 260, when Dom. Gulielmusde Dunlop was lord of Dunlop in Ayrshire, an estate still in possession of the family.
Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.
Surname type: Location or geographical feature
Origin: Celtic
Region of origin: British Isles
Country of origin: Scotland
Religion of origin: Christian
Language of origin: Gaelic