This is not really a question, but I will attempt an answer. The moat was a ditch/canal filled with water and crossed using a drawbridge. It was a form of protection. The castled located on a "mott" or hill usually didn't need this form because they could see in all directions.
moat drawbrige portcullis
you should use it on a moat
The water-filled trench around a castle is called a moat.
Moat refers to a ditch filled with water, often used to help protect a fort or castle. Therefore, a suitable sentence would be "In medieval times, one defence often employed to deter attack upon a castle was the excavation of a deep moat."
cannons, soilders, paint, a tower, a moat. good luck. Make a draw bridge
I think that the 'trench' you are thinking of is a moat. You could say that it is a trench full of water that surrounds the castle. If you are not thinking of a moat then I am sorry.
Usually there is a moat around the castle. Apon being cleared to enter, a drawbridge was lowered covering the moat and a visitor would ride his horse over , the the drawbridge would be raised again to keep out unwelcome guests. (the electric gate of today serves the same purpose except for the moat)
A moat is a body of water that circles a castle, and a drawbridge is part of the castle that lowers to allow people to cross the moat.
The moat cleaners. ;)
the moat around the castle was there to protect the castle when it came under attack. A moat is basically a circle river dug around the castle. Hope this helps
The moat is filled with sharks
A homonym for the trench around a castle could be "moat."