1. the final stones placed at the top of a wall or structure
Usage: architecture; construction
2. the crowning achievement or final element that completes something
Usage: figurative
3. final academic projects or courses that demonstrate mastery of a field of study
Usage: education

Examples

• The mason carefully placed the capstones along the top of the garden wall.
• The bridge’s capstones were carved with decorative patterns.
• Winning the championship was the capstone of her athletic career.
• The peace treaty served as the capstone to years of diplomatic efforts.
• Students must complete their capstone projects before graduation.
• The capstone course integrates everything learned in the program.
• His final novel was the capstone of a distinguished writing career.