terreplein

Etymology

Originally a borrowing of Italian terrapieno (“earth-fill(ed)”), later altered after the model of French terreplein (now terre-plein). Its former misspellings arose from confusion of the second element of the name with Italian piano or French plain, plane (“flat, level”) based on the appearance of the earth-filled central platforms of walls.

noun

1. (obsolete military) The sloping earthen embankment behind a defensive wall.
2. (military) The level platform atop a wall, typically protected by a parapet and (strictly) distinguished from the slightly higher banquette used by its defenders.
3. (military) Any level base used by artillery in the field.
4. (civil engineering) Any earthen embankment with a broad level top, such as those used for a canal elevated above a valley floor.