YANKEE

Who a yankee is has been answered differently throughout the years by different people. To most people of the world, a Yankee is an American. To most Americans, he is a descendant of old New England stock. But to Southerners, a Yankee is a Northerner — someone from north of the Mason-Dixon line. But during a period of national crisis, such as World War I, Americans are all Yankees.
The origin of the term yankee has been a matter of dispute among etymologists since the days of the Founding Fathers. Although no provable conclusion is available, some notions sound authoritative.
Yankee appears to have started life as a disparaging nickname for a Dutchman, and it is thought that it may represent Janke, a diminutive form of «John», perhaps used originally of the Dutch of New Amsterdam. The idea that enjoyed the largest following was that «Yankee» came from the epithet Jan Kees — a dialectal variant of John Kaas, which literally meant «John Cheese», an ethnic insult for a Hollander. Jan pronounced Yahn was «John», and cheese was the national product of Holland.
Another notion espoused by some word historians is that the Dutch living in New York applied the terms to the English — who had moved into Connecticut — viewing them as country bumpkins, and mockingly calling them Yankees. But the English during the Revolutionary War extended the meaning further. They attached what was construed as a belittling tag to all residents in the northern territory; Yankees became the British nickname for the colonists.
According to James Fenimore Cooper, Indians sounded the word English as Yengees: whence Yankee. In 1841 he appended a note in The Deerslayer. «It is singular there should be any question concerning the origin of the well-known sobriquet of ‘Yankee.’ Nearly all the old writers who speak of the Indians first known to the colonists make them pronounce ‘English’ as ‘Yengees.’ « But this corrupted pronunciation has not been otherwise substantiated. Other ideas abound — for example, that the word was derived from the Scottish yankie, «a gigantic falsehood», or from the Dutch vrijbuiten, meaning «freebooter» or «plunderer».
The War between the States gave the word Yankee a derisive twist. The Confederate soldiers didn’t call the federal troops Northerners or Unionists but Yankees, and, to underscore the lowest meaning of this term, they prefixed it with «damn». The federal soldiers were not just Yankees; they were «damn Yankees».
During World War II Yankees became known as Yanks in Europe. Today both terms persist.