capstone
n.the final part of a project or a career that shows how much you have learned. It is like the top stone on a building that finishes it off.
n.the final project or experience in a series of studies or a career, serving as a culmination of one's knowledge and skills. Often used in academic contexts to describe a senior thesis or a final military assignment.
“The internship was the capstone of his college experience.”
“After years of training and fieldwork, the captain's final deployment served as the capstone of his distinguished military career.”
“The architecture program requires students to complete a capstone project that integrates all the technical and theoretical knowledge they have acquired over the previous four years into a single, functional design.”
From Middle English capston; equivalent to cap + stone.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.