Dien Bien Phu

from The American Heritage® Dictionary of the English Language, 5th Edition.

• A town of northwest Vietnam near the Laos border. The French military base here fell to Vietminh troops on May 7, 1954, after a 56-day siege, leading to the end of France's involvement in Indochina.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the French military base fell after a siege by Vietnam troops that lasted 56 days; ended the involvement of France in Indochina in 1954