mantlet walln.Fortificationhistorical a low outer wall or rampart; cf. mantle-walln.
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1951 H. BraunIntrod. Eng. Mediaeval Archit. (1967) xi. 215 The method employed in the Edwardian period was to surround the castle with a ‘list’ or border, itself protected by a low stone wall called a ‘mantlet’ wall.