An armistice is the effective end of a war, when the warring parties agree to stop fighting. The most famous armistice, the one still meant when people say simply "The Armistice", is the one at the end of World War I, on November 11, 1918. Armistice Day is still celebrated in some places on the anniversary of that armistice; alternatively November 11, or a Sunday near to it, may still be observed as Remembrance Day.
An armistice is a modus vivendi and is not the same as a peace treaty, which may take months or even years to agree on. The armistice of 1953 in the Korean War has, as of November 2004, not yet been followed by a peace treaty.