moats

noun

1. 1

   A deep, wide defensive ditch, normally filled with water, surrounding a fortified habitation.

2. 2

   An 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. 3

   A circular lowland between a resurgent dome and the walls of the caldera surrounding it.

4. 4

   A hill or mound.