Definition of casemate in US English:



  • 1A small room in the thickness of the wall of a fortress, with embrasures from which guns or missiles can be fired.

    • ‘Historically, one casemate of the fortress was maintained as the ‘Fern Room’ with the interior walls and ceiling completely covered by lush growth of Adiantum capillus-veneris.’
    • ‘These vaulted casemates form the main walls of the fort and support the wide gundeck, the roof of the Castillo.’
    • ‘He endorsed the construction of works with high stone or brick walls, the guns arranged in multilevel tiers of internal chambers called casemates, and firing done through iron-shuttered embrasures piercing the facade.’
    • ‘In Champagne, at Beausejour, we demolished an enemy gun protected by a casemate which was enfilading our trenches.’
    • ‘Guns usually stood on a flat terreplein, shooting over a wide earth parapet which was intended to absorb incoming fire, although they might also fire through splayed embrasures, or be housed in vaulted casemates on a lower storey.’
    1. 1.1 An armored enclosure for guns on a warship.
      • ‘Following the deck above the turret back out to daylight, the first two of the secondary 5.9in guns are accessible, with the armoured casemate broken open to give a view of the breech mechanisms.’


Mid 16th century: from French, from Italian casamatta, perhaps from Greek khasma, khasmat- (see chasm).