Definitions
1.nounA deep, wide defensive ditch, normally filled with water, surrounding a fortified habitation.
2.nounAn aspect of a business which makes it more "defensible" from competitors, either because of the nature of its products, services, franchise or other reason.
3.nounA circular lowland between a resurgent dome and the walls of the caldera surrounding it.
4.nounA hill or mound.
5.verbTo surround with a moat.