The name Ku Klux Klan seems to have many theories about its origin. The fact remains that there is no one verifiably documented version of its origin. Although the most popular origin theory is that the name has Greek and Gaelic origins. This is how it goes:

Kyklos: means 'circle' in Greek

Clan: Gaelic for a group

Kyklos + clan = Ku Klux Clan

The origin of the Klan can be traced back to 1865, Pulaski, Tennessee (present day USA). A group of confederate soldiers from the South, led by  Nathan Bedford Forrest formed the Klan and for a short period of time they went by the name 'Kuklux Clan. Throughout its history, the group both gained and waned in popularity.