capstone

[ kap-stohn ]
/ ˈkæpˌstoʊn /

noun

a finishing stone of a structure.
the crowning achievement, point, element, or event.

Origin of capstone

1350–1400; Middle English. See cap1, stone
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for capstone

British Dictionary definitions for capstone

capstone

copestone (ˈkəʊpˌstəʊn)

/ (ˈkæpˌstəʊn) /

noun

one of a set of slabs on the top of a wall, building, etc
mountaineering a chockstone occurring at the top of a gully or chimney
a crowning achievement; peakthe capstone of his career
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012