From Wikipedia, the free encyclopedia.
A navy is a military organisation that primarily operates on the sea.
Most (but not all) armed forces make considerable organisational distinction between the land-based warfare of an Army, the sea-based warfare of a Navy, and the air-based warfare of an Air Force - often splitting the three components into mostly independent forces.
Many navies include ground forces (marines) to fight on land and defend sea craft.
In many countries, the navy is the oldest branch of the armed services. Hence, for example, the British term "the Senior Service".
See also Modern Naval tactics, sea power.
Merchant navy is a British and Commonwealth term for the civilian seafaring industry, recognizing both the shared hazards of seafaring activity during wartime, as well as the expectation that civilian vessels may be put under various kinds of control by military authorities. In the USA the equivalent term is merchant marine.