Jack Ketch (?). [Perh. fr. Jack, the proper name + Prov. E. ketch a hangman, fr. ketch, for catch to seize; but see the citations below.] A public executioner, or hangman. [Eng.][1913 Webster]
The manor of Tyburn was formerly held by Richard Jaquett, where felons for a long time were executed; from whence we have Jack Ketch.
[Monmouth] then accosted John Ketch, the executioner, a wretch who had butchered many brave and noble victims, and whose name has, during a century and a half, been vulgarly given to all who have succeeded him in his odious office.