To defend means to protect someone or something from attack, harm, or criticism. When a soccer goalie defends the net, she positions herself to stop the other team from scoring. When you defend your little brother from a bully, you stand up for him and help keep him safe.

A lawyer defends their client in court by arguing their innocence. A student might defend their answer in class by explaining the reasoning behind it. Countries maintain armies to defend their borders, and castles were built with thick walls to defend against invaders.

You can also defend ideas and beliefs. When you defend your opinion about which book the class should read, you give reasons why your choice makes sense. This kind of defending uses words and logic instead of physical protection, but the core idea remains the same: you're protecting something you value from being dismissed or defeated.

The opposite of defending is attacking or abandoning. A good friend knows when to defend you, even when you're not there to defend yourself.