Webster's Revised Unabridged Dictionary · 1913

Terreplein

Terreplein , noun

[French, from Latin terra earth + planus even, level, plain.]

1.
(Fortification) The top, platform, or horizontal surface, of a rampart, on which the cannon are placed. See Illust. of Casemate.
2.
(Civ. Engineering) An embankment of earth with a broad level top, which is sometimes excavated to form a continuation of an elevated canal across a valley.