Okay, so imagine you and your friends are playing a really big game, like soccer or basketball. There are some friends who are really good at the game and some who aren't as good. Now, imagine that you and your friends are all countries in the world, and the game you're playing is called international politics.
In international politics, there are some countries that are really big, like the United States or China, and they have a lot of power and influence. But there are also some countries that are not as big, but they still have some power and influence. These countries are called middle powers.
Middle powers are like the friends who are pretty good at the game, but not the best. They might not be able to win the game by themselves, but they can still make a big difference and help their team (or in this case, the world) in important ways.
Middle powers often work together with other middle powers or larger powers to accomplish things like promoting peace, fighting climate change, or helping poorer countries. Even though they might not have as much power as bigger countries, they can still play a really important role in the world.