I'm glad you asked this question Jack. Although internet legend claims the "World Series" had to do with the New York World newspaper sponsoring the contest (hence it supposedly being originally called "the World's Series), this is not true. Fact is that the title "World Series" started in the late 19th century when the only baseball in the world - at least at the professional level - was played in the U.S.A. and so the powers at the time decided to call it the World's Championship Series. As other countries became more active in baseball, nobody ever decided to change the name or to include teams from outside the U.S.A. as we do with Little League baseball's world series. So the term is really just an old one that continues to be used in modern times. I imagine Japan could petition the U.N. and demand a change, but baseball will always be known as "America's pastime".