The Collaborative International Dictionary of English v.0.48:
Kuklux \Ku`klux"\, Ku Klux \Ku` Klux"\, Ku Klux Klan \Ku` Klux"
The name adopted in the southern part of the United States by
a secret political organization, active for several years
after the close of the Civil War, and having for its aim the
repression of the political power of the freed negroes; --
called also Kuklux Klan and the Klan. It exerienced a
revival in the 1920's, in the north as well as the south, and
persists as a weak organization into the 1990's. Its goals
were primarily anti-negro and anti-Catholic, and its tactics
included terrorist attacks on negroes for the purpose of
intimidation with the goal of continuing segregation. The
signature activity of the Klan was the burning of a cross,
either at rallies of Klansmen, or on the property of
African-Americans which they hoped to intimidate.
[1913 Webster +PJC]