Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.
DOUGLAS
As described in historical dictionaries
Patronymica Britannica (1860)
DOUGLAS. The most powerful and widely celebrated famil3'that Scotland ever produced. The name was assumed from lands on the small river Douglas, in Lanarkshire, (Gael, diif-glas, du-cjlas, i.e., dark grey, from the colour of its waters), where William of Dufglaswas established as early as 1175. This illustrious race, renowned throughout western Europe for its romantic career, may well be accounted an "historical " family, for as Hume, the annalist of the House, has it —
Surname type: From given name or forename
Origin: Celtic
Region of origin: British Isles
Country of origin: Scotland
Religion of origin: Christian
Language of origin: Gaelic