The story
- Old French · derived frombataillement
- Middle English · inherited frombatilment
- English todaybattlement
From Middle English batilment, from Old French bataillement, earlier bastillement (“fortification”), from bastillier (“to fortify, to equip with battlements”), from bastille (“fortress”) (see bastion). By surface analysis, battle + -ment.
Etymology from Wiktionary, CC BY-SA 4.0.