10 letters · 12 points in Scrabble
noun level space where heavy guns can be mounted behind the parapet at the top of a rampart
originOriginally 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.
Etymology from Wiktionary, CC BY-SA 3.0