(origin: Gaelic. Local) From the County of Lennox, Scotland. The original name was Leven-ach, the field on the Leven, from the river Leven, which flows through the county, called in Latin Levinia. The river was so called from Llyfn, in the Welsh, which signifies a smooth, placid stream. Leven-achs, for a while spelt and written Levenax, and finally Lennox. Arkil, a Saxon, a baron of Northumbria, who took refuge from the vengeance of the Norman William under the protection of Malcom Canmore, appears to have been the founder of the Lennox family.

Arthur, William (1857) An Etymological Dictionary of Family and Christian Names. New York: Sheldon, Blakeman. Public Domain.

LENNOX. The ancient county of Dinnbarton, Scotland, once mucli more extensive than now. The original name of the district was Leven-ach, ' the field of the Leven,' and designated not the basin only of that river, hut also of Loch-Lomond, once called Loch-Leven. Levenachs came to he the name applied to the extensive possessions of the powerful Earls of the soil, and hence Levenax and Lennox. Imp. Gaz. of Scotland.

Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.