The Nuttall Encyclopedia
Slang name for a New Englander; applied in England to the citizens of the United States generally; it is of uncertain derivation.
Wood, James, ed. Entry for 'Yankee'. The Nuttall Encyclopedia. https://www.studylight.org/encyclopedias/eng/nut/y/yankee.html. Frederick Warne & Co Ltd. London. 1900.