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1. Keep: The innermost and strongest part of the castle, usually a tall, round tower.
2. Bailey: The courtyard of the castle, surrounded by walls.
3. Gatehouse: The main entrance to the castle, usually fortified with towers and a portcullis.
4. Arrow slits: Narrow openings in the walls for archers to shoot arrows from.
5. Crenellations: The battlements at the top of the walls, providing cover for defenders.
6. Machicolations: Openings in the walls above the gatehouse, allowing defenders to drop objects on attackers.
7. Portcullis: A heavy, spiked gate that can be lowered to block the entrance.
8. Drawbridge: A bridge that can be raised or lowered to allow access to the castle.
9. Moat: A ditch filled with water surrounding the castle, making it more difficult for attackers to reach.
10. Sally port: A small, hidden gate used by defenders to make surprise attacks on attackers.