Behavior is how someone acts or conducts themselves. Your behavior includes everything you do: how you treat others, whether you follow rules, how you respond when things go wrong, and the choices you make throughout your day.

At school, teachers might talk about classroom behavior, meaning whether students listen quietly during lessons, raise their hands to speak, and treat classmates with respect. At home, your parents notice your behavior too: whether you do your chores without complaining, how you speak to your siblings, and what you do when no one's watching.

Behavior includes both big decisions and small, everyday actions that show who you are. Do you return lost items you find? Do you keep playing fairly when you're losing? Do you help someone struggling with heavy bags? These behaviors reveal your character.

Scientists study animal behavior to understand how creatures live, hunt, communicate, and survive. A zoologist might observe the nesting behavior of birds or the hunting behavior of wolves.

The word can also describe how things work or react. Scientists might study the behavior of chemicals when mixed together, or engineers might test the behavior of a bridge under heavy weight. When something doesn't work as expected, we might say it's behaving strangely.