Arthur, William (1857) An Etymological Dictionary of Family and Christian Names. New York: Sheldon, Blakeman. Public Domain.
LEVEN
As described in historical dictionaries
An Etymological Dictionary of Family and Christian Names (1857)
(origin: Local) A river in Lancashire, England, also a town, lake, and river in Lennox, Scotland, whence the county derives its name. (See Lennox.) From the Welsh Llyfn, smooth, placid--the smooth river. The Gaelic Liomha-abhainn, pronounced Le-avon, signifies the same thing.
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