Well kiddo, a salvo is when a lot of things are fired at the same time. Imagine you have a bunch of little toys, like toy soldiers or toy cars, and you line them up really close to each other. Then, you take a big hand and push them all forward at the same time. That's kind of like a salvo!
But usually when people talk about a salvo, they mean something a little bigger than toys. It might be a bunch of missiles or rockets that are fired all at once. They might be fired from a big ship or a plane or even a little launcher that people carry around on their shoulders.
And sometimes, a salvo can also mean a bunch of gunshots that are fired all at the same time. You might hear this in movies or on TV when soldiers are attacking something or when there's a big battle.
So overall, a salvo is just a word that means a lot of things are being fired at the same time. It's kind of like a big push that sends everything forward all at once.