a final touch; a crowning achievement; a culmination
同义词：finishing touch, copestone
a stone that forms the top of wall or building
同义词：copestone, coping stone, stretcher
capstone详细解释
cap.stone n.（名词）The top stone of a structure or wall.拱顶石，压顶石，顶层石：建筑物或墙的最上面一层石头The crowning achievement or final stroke; the culmination or acme.顶点：登峰造极的成就或最后一次成功的努力；终极或极点
