| A | B |
|---|
| a notched battlement made-up of alternate crenels (openings) and merlons (square sawteeth) | crenelation |
| a round tower built into a wall | drum tower |
| the complex of towers, bridges, and barriers built to protect each entrance through a castle or town wall | gate house |
| a wooden bridge leading to a gateway, capable of being raised or lowered | drawbridge |
| a narrow wall built along the outer edge of the wall walk to protect soldiers against attack | battlement |
| a big ditch filled with water that surrounds a castle | moat |
| having two set of walls, one inside the other | concentric |
| part of a battlement, the square "sawtooth" between crenels | merlon |
| the passage behind the parapet of a castle wall | allure |
| a narrow vertical slit cut into a wall through which arrows could be fired from inside | arrow loop |
