What kind of a family changes their name from "Black" to an object that carries a dead body?

sor-os' Definition

1. an urn or receptacle for keeping the bones of the dead
2. the funeral couch or bier on which the Jews carried their dead forth to burial https://www.biblestudytools.com/lexicons/greek/nas/soros.html

Also coffin: https://www.wordhippo.com/what-is/the-meaning-of/greek-word-4e8ecdfae56267de8ddb30a59f618be7360874b4.html

Family name history here: https://www.jewishvirtuallibrary.org/george-soros