Reader acw sent in the eggcorn "sir name" for surname. The 3580 hits in Google are things like this:
(link) The goals of this project are to provide others the opportunity to verify their relationship to the Ledford Sir Name Genetically and Identify the Genetic Roots of our Ancestry.
As the AHD explains, surname is from French sur+nom. This has nothing to do with sir, which is a variant of sire, which is from Latin senior by way of Old French and Middle English. But it's a classic "sporadic folk etymology" to make the connection.Posted by Mark Liberman at July 3, 2004 11:01 AM