笠かさ石いし

noun

coping stone; capstone

A stone placed on top of a wall, pillar, or roof to protect it from weathering and provide a finished appearance. Used in traditional Japanese architecture and stonework.

• 石いし垣がきの上うえに笠かさ石いしを載のせて雨う水すいの浸しん入にゅうを防ふせぐ。

  A coping stone is placed on top of the stone wall to prevent rainwater from seeping in.