A deep, wide ditch filled with water surrounding a castle or fortified place to protect it from attackers.
From Old French 'mote,' possibly related to 'motte' (mound). Medieval castles built moats as water barriers around their defensive structures, a practice that spread throughout Europe.
Moats were genius because they combined three defenses: they were hard to cross, prevented siege equipment from getting close, and reflected light making sneak attacks harder at night.
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