A defender is someone who protects something or someone from attack or harm. In soccer or hockey, defenders position themselves between the other team and their own goal, trying to block shots and stop opponents from scoring. In a courtroom, a defense attorney defends people accused of crimes by arguing their case and protecting their rights.

When a castle was under siege in medieval times, its defenders fought to keep invaders out. Today, you might defend your little brother from a bully, defend your favorite book when someone criticizes it, or defend a scientific theory by explaining why it makes sense.

A defender doesn't always use physical force. Sometimes defending means using words and arguments. When you defend your position in a debate, you're giving reasons why you believe you're right. When someone defends their honor, they're standing up for their reputation.

The key idea is protection: a defender stands between something valuable and whatever threatens it. Whether guarding a goal, protecting the innocent, or standing up for an idea, defenders take a protective stance.