early 14c., from Old French bataillement, earlier bastillement "fortification," from bastillier "to fortify, to equip with battlements," from bastille "fortress, tower" (see bastion). The raised parts are cops or merlons; the indentations are embrasures or crenelles.
a parapet wall or balustrade surrounding the flat roofs of the houses, required to be built by a special law (Deut. 22:8). In Jer. 5:10, it denotes the parapet of a city wall.