Arthur, William (1857) An Etymological Dictionary of Family and Christian Names. New York: Sheldon, Blakeman. Public Domain.
BLAIN
As described in historical dictionaries
An Etymological Dictionary of Family and Christian Names (1857)
(origin: Fr. Local) From the town of Blain, in Bretagne, France. Blaen, in the Welsh, signifies the summit or top; the same as pen, brig, and bar, the highest part of a mountain; the end or top of an object; the inland extremity of a glen; a leader or chief.
Patronymica Britannica (1860)
BLAIN. See Blane.
Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.
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