An admiral of the fleet or fleet admiral (sometimes also known as admiral of the navy or grand admiral) is a military naval officer of the highest rank. In many nations the rank is reserved for wartime or ceremonial appointments. It is usually a rank above admiral (which is now usually the highest rank in peacetime for officers in active service), and is often held by the most senior admiral of an entire naval service.
It is also a generic term for a senior admiral in command of a large group of ships, comprising a fleet or, in some cases, a group of fleets. If actually a rank its name can vary depending on the country. In addition to "fleet admiral" and "admiral of the fleet", such rank names include "admiral of the navy" and "grand admiral".[Note 1]
The title admiral of the fleet can trace its origins to the Middle Ages, where the title was typically granted to a nobleman who was appointed by a monarch to raise and command a navy for a specific campaign.