Definition of "capstone" [cap•stone]

• The top stone of a structure or wall. (noun)
• The crowning achievement or final stroke; the culmination or acme. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Colleges also could promote "high-effort" practices across the curriculum, such as challenging freshman seminars, writing-intensive courses, undergraduate research assignments, service learning and long-term "capstone" projects."
• "Zechariah then instructed him to bring out the capstone, which is the final piece of stone set aside to mark completion of the temple."
• "Where your capstone is a detailed, immaculately researched document, a presentation has to keep to a strict time limit, usually around 20 minutes."