First, where do the terms come from?
The word ‘castle’ comes from the Anglo-Norman French word ‘castel‘, which itself derives from the Latin word meaning ‘fort’. A castle is a fortified dwelling. In other words, there are many kinds of fortifications built for defense, but a castle is specifically used as a residence, as well. In medieval times, castles were usually occupied by someone highborn, such as a lord, knight or monarch. (Shown here is Bodium Castle, England.)
The term ‘palace’ comes from Rome’s Palatine Hill, where the rich and famous built their sumptuous homes in Roman times. So when we’re wondering what’s the difference between a castle and a palace, the most important difference is that a palace is not fortified.
What are the characteristics of a castle?
Castles, as we know them, began to be built in the eleventh and twelfth century, although often based on existing fortifications. Because they were built for defense, castles are usually built of strong stone. They’re located where they can be easily defended, such as on a high hill or protected by a river to prevent invasion from the enemy. They’re designed to make entry extremely difficult.
Castles were often surrounded by a moat to make tunneling during a siege impossible. There are often walkways and crenellations on the roof for soldiers to patrol, and windows are narrow to allow archers to fire out at the enemy without risking their own safety.