A "moat" is a deep, wide ditch that surrounds a castle or fort, often filled with water. Its main purpose is to protect the structure from attackers, making it harder for enemies to reach the walls. By creating this barrier, castles like those built in the Middle Ages could defend themselves more effectively against sieges. In a broader sense, the term "moat" is also used in business to describe a company's competitive advantage. Just like a physical moat protects a castle, a strong business moat, such as a unique product or brand loyalty, helps a company fend off competitors and maintain its market position.