A nickname for a native or citizen of new England, especially one descended from old new England stock; by extension, an inhabitant of the northern states as distinguished from a Southerner; also, applied sometimes by foreigners to any inhabitant of the united States. From meanness first this Portsmouth Yankey rose, And still to meanness all his conduct flows. (Oppression, A poem by an American (Boston, 1765))
According to Thierry, a corruption of Jankin, a diminutive of john, and a nickname given to the english colonists of Connecticut by the dutch settlers of new York. Dr. W. Gordon (Hist. Of the Amer. War, ed, 1789, vol. I, pp. 324, 325) says it was a favorite cant word in Cambridge, mass, as early as 1713, and that it meant excellent; as, a yankee good horse, yankee good cider, etc. Cf. Scot yankie a sharp, clever, and rather bold woman, and Prov. E. Bow-yankees a kind of leggins worn by agricultural laborers.
Origin: Commonly considered to be a corrupt pronunciation of the word English, or of the French word Anglais, by the native Indians of America.