Bullying vs. Mean/Rude Behavior
When someone says or does something intentionally or unintentionally hurtful ONCE, that's RUDE and MEAN. It is not bullying when two peers with no perceived power imbalance fight, have an argument, or disagree. Conflict resolution or mediation is appropriate for these situations.
When someone does something intentionally hurtful and mean that is repeated and involves and imbalance of power that's BULLYING. Bullying is a form of harassment that can happen to anyone but may be based on race, gender, height, weight, religion, ethnicity, sexual orientation, gender identity, gender expression, familial status, disability or medical condition.
Bullying may be physical (pushing, kicking) verbal (insults, threats), emotional/psychological (spreading rumors, manipulating) and cyber (using the Internet ie. Twitter, Facebook, cell phones to bully others).