battlement (n.)youdaoicibaDictYouDict[battlement 词源字典]
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.[battlement etymology, battlement origin, 英语词源]