The definition of behavior is simply, anything that a person does or the way that a person conducts himself. (It does not matter whether this is positive or negative.) Everything that we do is behavior. Waking up, brushing our teeth, eating breakfast, running to catch the bus... that's all behavior. Recycling is a behavior, but so is throwing trash on the ground. Helping an elderly woman cross the street is a behavior. So is painting graffiti on a wall. Everything we do, good or bad, is a behavior.
In contrast, misbehavior is defined as behavior that is not appropriate for the situation. Misbehavior is something that people might consider "wrong" or "bad". In typical American schools, misbehaviors might include hurting another student, destroying property or materials, or being disrespectful towards teachers or other students.
Behavior and misbehavior are similar because really, one cannot exist without the other. Nobody, including adults can behave completely appropriately 100% of ...
This answer begins by comparing and contrasting the definitions of behavior and misbehavior. It goes on to give the definitions of discipline and behavior management. I talk about how discipline and management are related to one another and how they are different. I also explain how discipline and behavior management are related to behavior and misbehavior. Finally, I consider the role of the teacher in both discipline and behavior management.