Casemate
A casemate is a fortified gun emplacement or armoured structure from which guns are fired, in a fortification, warship, or armoured fighting vehicle. When referring to antiquity, the term "casemate wall" means a double city wall with the space between the walls separated into chambers, which could be filled up to better withstand battering rams in case of siege (see § Antiquity: casemate wall.) In its original early modern meaning, the term referred to a vaulted chamber in a fort, which may have been used for storage, accommodation, or artillery that could fire through an opening or embrasure.