Total war is when a country gets into a big fight with another country, where everyone in the country helps. Even people who aren't in the army help in other ways, like by making things that the soldiers need, or by giving money or food to support the war.
In total war, the entire country is focused on winning the war. Everyone works together to try to defeat the enemy. This means that the government might control what people can do or say, and may even take away some of their normal rights, like freedom of speech or movement.
The goal is to do whatever it takes to win the war, even if it means lots of people die or things get destroyed. It is a very serious and scary time for everyone involved, but people believe that it's important to fight for what they believe in.
Some examples of total wars include World War I and World War II.