capstone
nounUK /ˈkæp.stəʊn/
US /ˈkæp.stoʊn/
A capstone is the top stone that finishes the building.
The workers placed the capstone on the wall.
OTHER MEANINGS
2. The final project that shows everything you learned.
Her capstone project was a small robot.
3. The best or most important part of something.
The concert was the capstone of the festival.
4. A stone placed on top of a wall or pillar.
The old pillar still had its capstone.