There are many types of bullying: cyber, physical, and emotional.
Bullying is when someone makes you feel unwanted or when you feel like you don't belong somewhere.
I have felt that way before and just not realized that I was being bullied.Some people don't even know that they are bulling someone and then when they do their self confidence shrinks and they start to feel like they need to bully there selfs. In my experience I have been bullied before, and can I say its not the most pleasant thing in the world.
After a while you learn to stand up for yourself and feel confident. Even if the person doesn't think they are bullying you. If what they say or what they do hurts you, stand up!