donjon

/ˈdɑndʒən/
noun
  1. The main tower or central stronghold of a medieval castle, often used as a last refuge during an attack.
    • The lord and his family retreated to the donjon when the castle walls were breached.
    • From the top of the donjon, the guards could see enemies approaching from miles away.
    • The castle's donjon was built of thick stone to withstand sieges.
Synonyms
What does "donjon" mean? | whatsthatwordmean | whatsthatwordmean