Why is the ninth month called September?
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.