Bullying can mean doing or saying something that deliberately hurts, threatens or frightens someone.
People who bully do so for all kinds of reasons. It can be because of things like race, religion or sexuality. It can even be because of the way someone looks or because they are bright and intelligent.
Whatever the reason, it's important to remember that bullying is not normal. No one deserves to be bullied - simple as that.
Use this site to find out how to sort out the situation you're in or where to go if you need help.
If you need to talk to someone right now, you can call ChildLine free and confidentially on 0800 1111.