glacis

plural glacises

1. A gentle incline.

   The foam of these great ruins mounts in an instant to the ridge of the sand glacis, swiftly fleets back again, and is met and buried by the next breaker.

   1880, Robert Louis Stevenson, “The Old Pacific Canal: The Woods and the Pacific”, in Across the Plains: With Other Memories and Essays, London: Chatto & Windus, […], published 1892, →OCLC, page 79

   1. geographyA gentle sloping landform created by the deposition or erosion of material.
   2. alsofigurativelyarchitectureA gentle incline in front of a fortification which protects it from cannon fire and exposes attackers to more effective return fire from defenders.

      [T]ook his place with solemn Air 'midst the rest, who kept their valiant faces And levelled weapons still against the glacis.

      1823 July 15, [Lord Byron], Don Juan. Cantos VI.—VII.—and VIII., London: […] [C. H. Reynell] for John Hunt, […], →OCLC, canto VIII, stanza XXXIV, page 128

      2 more examples

      I think, quoth Corporal Trim, with humble submission to your Honour’s better judgment,——that these ravelins, bastions, curtins, and hornworks, make but a poor, contemptible, fiddle-faddle piece of work of it here upon paper, compared to what your Honour and I could make of it were we in the country by ourselves, and had but a rood, or a rood and a half of ground to do what we pleased with: As summer is coming on, continued Trim, your Honour might sit out of doors, and give me the nography—(Call it ichnography, quoth my uncle,)——of the town or citadel, your Honour was pleased to sit down before,—and I will be shot by your Honour upon the glacis of it, if I did not fortify it to your Honour’s mind.

      1659, Laurence Sterne, chapter XXX, in The Life and Opinions of Tristram Shandy, Gentleman

      [T]heir hearts had failed them at the silence and the blaze of lighted ships from end to end of the harbour, with eerie beams of the searchlights revealing the bleakness of the glacis they would have to cross.

      1922 (date written; published 1926), T[homas] E[dward] Lawrence, “Book II: Opening the Arab Offensive. Chapter XX.”, in Seven Pillars of Wisdom: A Triumph, Garden City, N.Y.: Doubleday, Doran & Company, published 1937, →OCLC, page 130

      Synonyms: talus

   3. governmentIn full glacis plate: the angled armour plate on the front of a tank which protects it from projectiles; also (often nautical), such a plate protecting an opening (for example, on a ship).
   4. postalA device for sorting mail which slides parcels across a sloped surface.

1. An administrative district of Seychelles.