noun
castle
KAS-uhl/ˈkæsl/
A fortified residence with defensive walls and towers.
Thick stone walls and towers surround the castle's guarded entrance.

Etymology
Latin castellum was a diminutive of castrum, “fort.” The modern meaning preserves the defensive purpose: a castle is not merely a grand building but a fortified stronghold.
In context
to survive life in any medieval castle the first thing you need is walls often several feet thick they were the first line of defense against Invaders
More examples
- The medieval castle overlooks the river.
- Visitors cross a bridge to enter the castle.
- He moves his castle, the rook, along the open file.
Forms
castle · castles
Similar words
- fortress
- Emphasizes military defense rather than residence.
- palace
- Emphasizes a grand residence without necessarily defensive fortifications.