A hard, pointed outgrowths on the heads of some animals. They're usually made of a bony core covered by a tough material called keratin. Rhinoceros and goats have this.

Example

1. The deer used its horns to defend itself from the wolf.
2. The rhinoceros's horns are very strong and can be used to break down trees.
3. The antelope's horns are curved and can be used to fight off predators.