ETYM Old Fren. mote hill, dike, bank, French motte clod, turf: cf. Spanish and Portu. mota bank or mound of earth, Italian motta clod, Late Lat. mota, motta, a hill on which a fort is built, an eminence, a dike, Prov. German mott bog earth heaped up.
(Homonym: mote).
A ditch dug as a fortification and usually filled with water; SYN. fosse.
Ditch, often filled with water, surrounding a building or garden.
Some 5,000 moats exist in England alone, many dating from the 12th–13th centuries; some were built for defense and others as a status symbol.