Arthur, William (1857) An Etymological Dictionary of Family and Christian Names. New York: Sheldon, Blakeman. Public Domain.
SOMMER
As described in historical dictionaries
An Etymological Dictionary of Family and Christian Names (1857)
(origin: Fr.) From sommer, to sum or cast up; one who directs or commands. Summere, Dan., to sum up.
Region of origin: Europe
Country of origin: Germany
Language of origin: German