A Navy is a fleet of waterborne military vessels. It is a part of the armed forces of a nation.
It includes anything
- on surface (battle ship s, carriers, cruisers, destroyers),
- below surface (submarines)
- amphibious ships,
- and seaborne aviation.
- Also included is the support, communications, training, investigation
There exists also a Merchant Navy, which includes all commercial ships. But these are not under a single command. The use of the word "navy" for this fleet came from historical times, when private vessels could be converted for a military use.
List of books: Navy