This is how my school district defines it
Bullying definition wrote:
“Bullying” means systematically and chronically inflicting physical hurt or
psychological distress on one or more students or employees. It is further defined as:
unwanted purposeful written, verbal, nonverbal, or physical behavior, including but
not limited to any threatening, insulting, or dehumanizing gesture, by an adult or
student, that has the potential to create an intimidating, hostile, or offensive
educational environment or cause long term damage; cause discomfort or humiliation;
or unreasonably interfere with the individual’s school performance or participation, is
carried out repeatedly and is often characterized by an imbalance of power.
Bullying may involve, but is not limited to:
1. unwanted teasing
2. threatening
3. intimidating
4. stalking
5. cyberstalking
6. cyberbullying
7. physical violence
8. theft
9. sexual, religious, or racial harassment
10. public humiliation
11. destruction of school or personal property
12. social exclusion, including incitement and/or coercion
13. rumor or spreading of falsehoods
From what I have heard is that retaliation isn't really considered self-defense, and it also punishable. One girl in my school was bullied, and then she fought back. The bully didn't suffer any consequences, but the girl did get punished.
It's best to report anything to the school.