Genealogy / THE MEANING AND RESEARCH OF MY POLISH LAST NAME, SURNAME? [4500]

Hi All,
I am new to the forum and Polish genealogy....searching for meaning to the surname, Ciesiolka--family uses the American name Sankey, which makes no sense to me. What did all the immigrants do, get together and agree on a name for the family to use? Seems kind of random. Thanks for any help.