<p><strong>Noun</strong></p><ul><li>a deep, wide trench, usually filled with water, surrounding the rampart of a fortified place, such as a town or a castle</li><li>any trench, such as one used for confining animals in a zoo</li><li>a competitive advantage a business has in its field: The company's moat was reduced when the patent on the devices they sold expired</li></ul>