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 defence. 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.
Not to be confused with motte - an earthen mound with a flat top and with the bailey form a motte-and-bailey castle, however the term is derived from the same Old French word at motte, indicating that the two features were closely linked.
Leeds Castle is a castle in Kent, England, situated 5 miles (8 km) southeast of Maidstone. A castle has been situated on the site since 1119. In the 13th century it came into the hands of King Edward I, for whom it became a favourite residence, while in the 16th century, Henry VIII used it as a residence for his first wife, Catherine of Aragon. The castle seen today dates mostly from the 19th century and is built on islands in a lake formed by the River Len to the east of the village of Leeds. It has been opened to the public since 1976.