Battlement
Battlement (-ment) , noun
[Old English batelment; compare Old French bataillement combat, from batailler, also Old French bastillier, bateillier, to fortify. Compare Battle, n., Bastile, Bastion.]
(a)
(Architecture) One of the solid upright parts of a parapet in ancient fortifications.
(b)
(Architecture) The whole parapet, consisting of alternate solids and open spaces. At first purely a military feature, afterwards copied on a smaller scale with decorative features, as for churches.