castles: A fortified defensive building or structure. Strictly speaking, a castle was also a home, whereas a fort was purely defensive, but I have used castle for any fortified place. A castle may also have had a dungeon or donjon, a sort of prison for offenders and captured soldiers.
Synonyms:
fort , keep , garrison
![[p.210] The Tower of London](http://tn.fromoldbooks.org/Knight-LondonVolII/wm/big/vol2-p210-The-Tower-of-London-q75-267x200.jpg "[p.210] The Tower of London, from London (Volume II), by Knight, Charles")
