Okay, imagine two kids in a playground - let's call them Tom and Jerry. They used to fight and argue all the time, but suddenly they decided to be friends and stop fighting. This is what we call a peace dividend.
Now let's translate this to countries instead of kids. Imagine two countries that were enemies before, they may have had fights, wars, and disagreements. Then one day, they decide to be friends and stop fighting. This is also called a peace dividend.
When countries are at war, they spend a lot of money on weapons, soldiers, and other resources needed to fight the war. But when there is peace, they don't need to spend as much money on those things because they don't need to fight. This is where the peace dividend comes in.
When a country spends less money on weapons and military-related things, they will have more money left over to spend on other things that are important to their people, like health care, education, or building new things like roads or buildings.
So, in summary, when countries stop fighting and make peace, they can save money on things related to the fight which means they will have more money left to spend on other important things. That is why it is called a peace dividend.