A world government is an imaginary idea that all countries in the world would be ruled by one government. That one government would make all of the laws and countries would have to follow them. It's a bit like having a really big family and everyone having to agree on how to do things. A world government would also mean that no country would fight with each other and people from different countries would be able to work and travel together without any problems. Unfortunately, most people don't like the idea of a world government! People like to be able to choose their own government and rules, so a world government isn't likely to happen.