from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A deathblow delivered to end the misery of a mortally wounded victim.
- n. A finishing stroke or decisive event.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A final blow or shot given to kill a wounded person or animal.
French : coup, stroke + de, of + grâce, mercy.(American Heritage® Dictionary of the English Language, Fourth Edition)
Late 17th century, from French coup de grâce ("finishing blow"). Originally referring to a merciful stroke putting a fatally wounded person out of misery or to the shot delivered to the head of a prisoner after facing a firing squad. (Wiktionary)