Anatomy of a Castle: Battlements

Tower along the walls of Cahir Castle, Ireland

There are many defensive elements to a castle wall and many different terms associated with them. The walls themselves might be called battlements - a parapet on the top of a wall with spaced openings for shooting through. A parapet is simply a protective wall on the top of a roof. These opening in the wall are called crenellations as a whole. If you've seen a child draw a castle, they almost always include crenellations, the iconic notched parts on the top of castles. These crenellations also have parts: crenels (or embrasures) are the opening through which archers shoot, merlons are the raised parts which give the archer cover, and machicolations. Machicolations are a part of the wall that juts out with openings on the floor of the walkway through which an archer could also take aim, or defenders could drop things on the enemy below like stones, boiling water, hot oil, and sometimes dead and diseased animals. Also along the walls there is likely to be towers, also called turrets. These were usually round with arrow loops for better vantage points and defense. As I'm sure those laying siege to a castle also felt, it's taking us forever to get inside these walls!  

This is a battlement atop a wall made up of

1. crenel  2. merlon  3. machicolation

Raglan Castle, Wales

Example of corbelled Machicolations

Here you can see the sky through the openings of the machicolations, how they jut out from the towers and how the defenders could use them to drop stones or hot oil on those trying to break into the gate below. Raglan Castle, Wales

Example of an Arrow Loop through which Archers could shoot while being protected.

Outer Walls and Towers of Chepstow Castle where arrow loops can be seen.