Happy #openingday to those who celebrate. The word Yankee has a nebulous origin. Some think it could be an indigenous word, others from the Dutch name for John. What we do know is that eventually it would be used to describe northerners if you were from the south, or Americans if you're from Europe. The equating Americans with the term is why sportswriters in the early 20th century began to refer to the American League baseball club in New York as Yankees rather than highlanders.