A Battleship was a large armored warship with a main battery consisting of heavy caliber guns. During the late 19th and early 20th centuries the battleship was the most powerful type of warship afloat, and a fleet of battleships was vital for any nation which desired to maintain command of the sea. During World War II, the battleship was replaced by the aircraft carrier as the most powerful kind of warship afloat. Some battleships remained in service during the Cold War and the last were decommissioned in the 1990s. The word battleship was coined around 1794 and is a contraction of the phrase line-of-battle ship, the dominant wooden warship during the Age of Sail.