capstone

plural capstones

1. Any of the stones making up the top layer of a wall; a coping stone.
2. figurativelyA crowning achievement, culmination or finishing touch.

   “You see, I’ve never had a girl friend,” I added, by way of topping the obelisk of silliness with the capstone of fatuity.

   1904, Guy Wetmore Carryl, Far from the Maddening Girls, chapter 5

   1 more example

   Success of the Apollo program has been the capstone to a series of significant accomplishments for the United States in space in a broad spectrum of manned and unmanned exploration missions and in the application of space techniques for the benefit of man.

   1969, The Post-Apollo Space Program: Directions for the Future, NASA

present singular third person capstones · participle present capstoning · participle past capstoned · past capstoned

1. transitiveTo complete as a crowning achievement; to top off.

   Capstoning a decade's worth of linked short stories, The Quiet War (2008) was a vivid and tense novel about a solar system sliding into conflict.

   2012, Keith Brooke, Strange Divisions and Alien Territories, page 23

2. USinformaltransitivegovernmentTo train in the Capstone Military Leadership Program.

   “Capstoned” units are now able to train and plan in peacetime with the command with which they will fight in wartime.

   1981, Army Reserve Magazine, volumes 27-28, page 24