Board Thread:Naruto Discussions/@comment-26127155-20150326052215/@comment-6769189-20150418152156

World War is a war between many major countries(societies) in the world. World Health Organization isn't dedicted to keeping the planet healthy, but the people. I don't see the use of planetary world in those either. This is why I'm hesitant to believe world refers to the planet and not another continent, because despite literally meaning world, it doesn't mean Earth. Madara and Obito talk about changing the world, but they aren't attempting to change geological features or planetary properties. Ninja world doesn't mean the Earth is trained in the ways of the shinobi.