the.com/defence

means The act or system of protecting something from attack, harm, or criticism — or the case made in its favor.

from From Old French 'defens', rooted in Latin 'defendere' — 'de-' (away) plus 'fendere' (to strike), so literally 'to strike away'. The British/Commonwealth spelling keeps the French '-ence'; American English later shaved it to 'defense', a split that still causes low-grade transatlantic skirmishes.