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 peace-time 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.