Okay kiddo, a gun-free zone is a place where people are not allowed to bring guns. Just like how some places may have rules about not allowing pets inside, some places have rules about not allowing guns inside.
This kind of rule is usually put in place to keep people safe. Guns can be dangerous if someone doesn't know how to use them properly or if someone uses them to hurt others on purpose. So, if a place like a school or a hospital says that guns are not allowed inside, then people are less likely to bring guns in and use them to hurt others.
It's important to remember that not all places are gun-free zones, and some people might still have guns even if they're not supposed to. It's always a good idea to be aware of your surroundings and know what to do if you ever feel unsafe.