Final answer:
The French term for 'sliding door' used for the grating that protects a castle is 'Portcullis' (A). This feature, along with drawbridges, parapets, and moats, was integral to medieval castle defenses.
Step-by-step explanation:
The term from the French for 'sliding door' that is more commonly known as the grating protecting a castle is Portcullis (A). A portcullis is a heavy, vertically closing gate typically found in medieval fortifications, consisting of a latticed grille made of wood, metal, or a combination of both. It was lowered into place through grooves in the gateway walls to block entry, especially during attacks or sieges, serving as a formidable barrier.
Historical features like drawbridges, parapets, and moats also contributed to a castle's defenses. Drawbridges were movable bridges that allowed access across a moat or ditch when lowered but could be raised to prevent entry. Parapets were low protective walls along the edge of a roof or walkway, often crenellated for the defense of archers. Moats, often filled with water, surrounded a castle and acted as an initial deterrent against attackers.
The protective measures of castles bear comparisons to various parts of a church portal. For example, the tympanum and archivolts of gothic church portals, such as those seen on the Cathedral of Notre Dame de Chartres, serve as a different kind of gateway, leading visitors into a sacred space rather than fortifying against enemies.