Word of the Day -- Moat

A moat is a deep, broad ditch, either dry or filled with water, that surrounds a castle, other building or town, historically to provide it with a preliminary line of defense. In some places moats evolved into more extensive water defences, including natural or artificial lakes, dams and sluices. In later periods the moat or water defences may be largely ornamental.  In medieval times, moats were excavated around castles and castles as part of the defensive system as an obstacle immediately outside the walls. In suitable locations they might be filled with water. A moat made access to the walls difficult for siege weapons, such as siege towers and battering rams, which needed to be brought up against a wall to be effective. A water-filled moat made the practice of mining, digging tunnels under the castles in order to effect a collapse of the defences, very difficult as well. Segmented moats have one dry section and one section filled with water. Dry moats cut across the narrow part of a spur or peninsula are called neck ditches. Moats separating different elements of a castle, such as the inner and outer wards are cross ditches.

The word was adapted in Middle English from the Old French motte "mound, hillock" and was first applied to the central mound on which a castles was erected, and then came to be applied to the excavated ring, a "dry moat". The shared derivation implies that the two features were closely related and possibly constructed at the same time. The term moat is also applied to natural formations reminiscent of the artificial structure, and to similar modern architectural features.