__NOTOC__A glacis (IPA |/ˈgleɪ.sɪs/ or IPA |/ˈglæ.si/) in
military engineeringis an artificial slope of earth used in late European fortresses so constructed as to keep any potential assailant under the fire of the defenders until the last possible moment. On natural, level ground, troops attacking any high work have a degree of shelter from its fire when close up to it; the glacis consists of a slope with a low grade inclined towards the top of the wall. This gave defenders a direct line of sight into the assaulting force, allowing them to efficiently sweep the field with fire from the parapet.
The attackers are further frustrated by a deep ditch situated between the glacis and the wall itself, bounded on either side by the smooth, masoned scarp and counterscarp.
More generally, the term "glacis" can denote any slope, natural or artificial, which fulfils the above requirements. The etymology of this French word suggests a slope made dangerous with ice, hence the relationship with "
The term glacis plate describes the sloped front-most section of the hull of a
An erosional or depositional pediment, with little slope. Erosional glacis occur mostly in arid regions, and result from intense meteorization (weathering) and surface transport via laminar, episodic water flow.
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