間けん知ち石いし

noun

wedge-shaped stone used in stone walls; square stone narrowing at one end

Technical term in masonry and civil engineering for a stone block that is square at one end and tapers to a narrower end, used in constructing retaining walls and similar structures.

• この石いし垣がきには間けん知ち石いしが使つかわれている。

  This stone wall uses wedge-shaped stones.