Bullying
Bullying is unwanted, aggressive behavior among school aged children that involves a real or perceived power imbalance. Bullying includes actions such as making threats, spreading rumors, attacking someone physically or verbally, and excluding someone from a group on purpose.
Peer Conflict
It is not bullying when two kids with no perceived power imbalance fight, have an argument, or disagree. Conflict resolution or peer mediation may be appropriate for these situations.