Small tower on a castle

TURRET

Look for a protruding structure often used for defense or observation in medieval architecture.

The clue "Small tower on a castle" directly points to the answer "TURRET," which is a small, often cylindrical tower attached to a castle or fortification. It’s a straightforward definition with no wordplay or hidden meanings—just a clear description of a common architectural feature. If you’ve seen castles in movies or pictures, you’ve likely noticed these protruding structures used for defense or observation.