"The White Stripes announced the completion of Icky Thump on February 28, 2007. The title is derived from "ecky-thump", a Lancashire colloquial response of surprise, popularized by an episode of the 1970s UK comedy series The Goodies. On Later with Jools Holland (broadcast June 1, 2007) Jack attributed the album's name to its use as an exclamation by his wife, who is from Lancashire. He added that the deliberate misspelling was to make it easier for an American audience to identify with.5
The liner notes for Icky Thump also suggest the spelling variation was due to concerns over copyright infringement." From an entry at a well-known online encyclopedia.