Bailey: A castle courtyard.
Barbican: A stone building protecting the gateway or entrance of a castle.
Battlements: A parapet with indentations and raised portions (merlons). Battlements are sometimes called crenellations.
Buttress: Projection from the wall that provides extra support for the building.
Concentric: Castles built with rings of stone walls one inside the other.
Constable: Official in charge of a castle when the owner is absent.
Curtain: Connecting wall between towers of a castle.
Drawbridge: A movable bridge. Drawbridges usually moved horizontally.
Drum-Tower: A large circular tower that was usually low and squat.
Fosse: A ditch surrounding a castle.
Garderobe: A castle toilet. The garderobe was often a projection from the wall over the moat.
Gatehouse: A building protecting the entrance to a castle.
Great Hall: The main room in the building where the castle owner and his family lived.
Keep: Main stone tower of a castle. This large tower was also known as a donjon.
Lancet: Long, narrow window with pointed head.
Loop: Narrow opening in castle wall that was used by archers to fire on attacking soldiers.
Machicolations: Projecting stonework on the outside of castle towers or walls, with holes in floor for dropping missiles on people attacking the castle.
Moat: A deep wide trench round a castle.
Motte: A mound of rammed layers of soil. Some mottes were only about 5 metres (16 feet) high, but some were over 18 metres (60 feet). The Normans built wooden watchtowers on the top of their mottes.
Murder-Holes: Holes (also called meutrieres) in the roof or ceiling of a castle. Cold water could be poured through the holes to put out fires. These holes were also used for pouring scalding water, hot oil or other substances on soldiers who had managed to enter the castle.
Palisade: A strong timber fence built on top of an earth rampart.
Parapet: A low wall on the outer side of the main wall.
Portcullis: Grating made of metal and wood. The portcullis was dropped vertically from grooves to block passage through the gate of the castle.
Rampart: A defensive stone or earth wall surrounding a castle.
Shell-Keep: A wall surrounding the inner portion of the castle.
Solar: The upper living room of castle. The solar was usually situated above the hall and was used mainly as a bedroom.
Tower: A high building. Towers in castles were either square, many sided (polygonal), or round.
Turret: A small tower. A turret on top of the main tower was often the main observation point in a castle.
Wall-Walk: A passage along the castle wall.