“blockade: Action to prevent supplies reaching an enemy, either by placing ships outside its ports, troops outside a city or cutting off traffic across a country’s borders. Under international law a neutral merchant vessel attempting to breach a blockade may be confiscated by the blockading country. The tactic was first attempted in the Napoleonic wars when Britain’s navy blockaded France, Portugal, and Spain. A recent naval blockade was imposed on 12 April 1982 by Britain on the Falkland Islands to cut off supplies to Argentine troops occupying them; it was lifted following the retaking of the islands by British forces in May and June 1982.”
Excerpted from: Cook, Chris. Dictionary of Historical Terms. New York: Gramercy, 1998.