1. stones that form the top layer of a wall, especially those that cap and protect it
Usage: architecture; masonry
2. the finishing or crowning elements of something
Usage: figurative

Examples

• The mason carefully placed the copestones along the top of the garden wall.
• Weather had damaged several copestones on the old stone fence.
• The copestones protected the wall from rain and snow damage.
• Installing proper copestones would extend the wall’s lifespan significantly.
• These achievements were the copestones of her distinguished career.
• The final reforms served as copestones to decades of gradual change.