KKK is the short name of the Ku Klux Klan, a secretive white racist group in the United States. It began after the American Civil War and has come back in waves. Its members have used fear and violence against Black people and against others they wanted to shut out. In ordinary talk, KKK is never a joke and never a club you join for fun; it names a hate group. The letters are usually said one by one, or people say the full name. Though actually, in other countries the same three letters can stand for something else, but in English news and schoolbooks KKK almost always means this US group. Handle the word with care; it is heavy history, not slang.