Castle parts are in ALL CAPS.
Walls - protected the castle.
++In a concentric castle the space between the two walls was called THE OUTER WARD. The inner curtain encloses THE INNER WARD.
++The high parts of the wall were called MERLONS and they contained an ARROW LOOP and were topped by three spikes called FINIALS.
++The low parts of the wall were called EMBRASURES. These were created openings through which missiles could be dropped.
++Both curtain walls and towers were perfectly vertical, except along the bottom of the outer face, where it spread out at a sharp angle. The sloping base, called A BATTER, had two main functions. First, it strengthened the structure and, second, it created a surface off which stones and other missiles dropped from the tops of the walls would bounce toward the enemy.
PORTCULLIS was a metal or wood grate that was dropped vertically just inside the main gate to the castle.
BARBICAN - a stone structure that protected the gate of a castle. Think of it as a gatehouse. It usually had a small tower on each side of the gate where guards could stand watch.
BATTLEMENTS (or CRENELLATIONS)are the structures at the tops of the walls surrounding a castle. Think of the movies where archers are at the top of the wall and firing arrows between open slots down on the attackers. These shapes at the top (where the archers position themselves for battle) are battled battlements. They are also referred to as crenellations.
RAMPART - Picture the battlements in the previous definition. The battlements are the top sections of the outer wall of the castle. Now to access these battlements the archers would stand on a walk way that was a wall in it's own right. This walkway is built right up against the outer wall and is called the Rampart.
BUTTRESS. A masonry projection used as additional support for walls. Notre Dame Cathedral is a good example of the use of Buttresses.
The INNER WARD was the inside of the castle and was also called a BAILY.
Buildings in the inner ward:
++The GREAT HALL was a building that was used as a dining area and meeting place.
++The Kitchen where the food was prepared.
++The KEEP was where the lord and his family lived. It was the strong point of the castle.
++The KENNELS where the hunting dogs lived.
++Other buildings in the inner ward were stables and a blacksmith shop.
TOWERS also protected the castle.
The MOAT was protection for the castle--it was a ditch filled with water that surrounded the castle.