noun
water jump
Specifically a water-filled obstacle on a racetrack or equestrian course.
競馬の障害レースで、馬が水濠を飛び越えた。
In the steeplechase, the horse jumped over the water jump.
noun
moat; water-filled trench
A defensive ditch filled with water, typically surrounding a castle or fortification.
城の周りには深い水濠が巡らされていた。
A deep moat surrounded the castle.
Compound of 水 (water) and 濠 (moat, ditch). The spelling 水壕 uses 壕 (trench, dugout) as a variant.