Jack Ketch is a proverbial name for death or, sometimes, Satan, but it has its origins in an historical person. Jack Ketch (died 1686) was one of Charles II's executioners who became famous through the way he performed his duties during the tumults of the 1680's, when he was often mentioned in broadsheet accounts that circulated throughout England. He executed Lord Russell in Lincoln's Inn Fields in 1683 and the Duke of Monmouth (see the Monmouth Rebellion) in 1685. He was either very awkward or sadistic with his technique, and his victims were known to have suffered at their deaths. His name was thereafter used as a shorthand for the gallows.

The name for the hangman in the traditional version of Punch and Judy was named Jack Ketch after him.