The water-filled trench around a castle is called a moat.
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.
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."
at the main way in if the castle has a moat or ditch.if there not moat of ditch then there no drawbrigde un less the castle ramdom
castle's eg The castle's moat is now empty.
I would like a larger alligator for the castle's moat, please.
A Moat
A 'moat'