Final answer:
The main part of the medieval castle was called the keep. It was the central stronghold and living quarters of the lord and his family.
Step-by-step explanation:
The main part of the medieval castle was called the keep. The keep was the central stronghold of the castle, usually a tall tower or building where the lord and his family lived. It served as a defensive structure and a symbol of power and authority.
Learn more about Medieval castles