Armistice

An armistice is the effective end of a war, when the parties agree to stop fighting. The word comes from the Latin "arma", meaning weapons and "statium", meaning a stopping. 
A truce or ceasefire usually refers to a "temporary" stop of hostilities for an agreed limited time or within a limited area. A truce may be needed in order to negotiate an armistice. 
An armistice is not the same as a peace treaty, which may take months or even years to agree on. The 1953 Korean War armistice is a major example of an armistice which has not yet been followed by a peace treaty. 
The United Nations Security Council often demands cease-fire of parties in modern conflicts. Armistices are always negotiated between the parties themselves and are thus generally seen as more binding than UN cease-fire resolutions in modern international law. 
The most famous armistice is the Armistice with Germany at the end of World War I, on 11 November, 1918, signed near Compiègne, France, and effective at the "eleventh hour of the eleventh day of the eleventh month."