They are used to defend their country, or attack another country's army.

All possible men had been used to defend the gates.

Bring the military home and use them to defend our borders.

The two elephants are often used to defend each other.

Many airplanes are used by air forces to defend countries.

She can only use spears to defend herself and the others.

He called on his followers to use all available means to defend what was left of their country.

In some cases, a check can be used to defend against such tactics.

Like the former, it can be used to defend against jump attacks.

It was used to defend the city from attacks by ships.