"The 19th-century Klan was originally organized as a social club by Confederate veterans in Pulaski, Tennessee, in 1866. They apparently derived the name from the Greek word kyklos, from which comes the English “circle”; “Klan” was added for the sake of alliteration and Ku Klux Klan emerged. The organization quickly became a vehicle for Southern white underground resistance to Radical Reconstruction. Klan members sought the restoration of white supremacy through intimidation and violence aimed at the newly enfranchised Black freedmen. A similar organization, the Knights of the White Camelia, began in Louisiana in 1867."
https://www.britannica.com/topic/Ku-Klux-Klan