File:Yankee, etymology of - Passages from the Diary of Christopher Marshall, p. ix (1849).jpg

Summary
(From the Evening Post, No. 53.) When the New England colonies were first settled, the inhabitants were obliged to fight their way against many nations of Indians. They found but little difficulty in subduing them all, except one tribe, who were known by the name of Yankoos, which signifies invincible. After the waste of much blood and treasure, the Yankoos were at last subdued by the New Englanders. The remains of this nation (agreeably to the Indian custom) transferred their name to the conquerors. For a while they were called Yankoos, but from a corruption common to names in all languages, they got through time to the name of Yankees, a name which, we hope, will soon be equal to that of a Roman or an ancient Englishman.