Admiral of the navy

Admiral of the navy is a senior-most rank of a naval service. Some navies use the term admiral of the navy as a title bestowed upon a fleet admiral or other senior naval official.

Germany
During World War II, the German Kriegsmarine referred to the senior most grand admiral as an admiral of the navy, known in German as Oberbefehlshaber der Kriegsmarine.

United States
George Dewey is the only American naval officer ever promoted to the U.S. Navy rank of admiral of the navy. He was promoted on March 24, 1903, retroactive to March 2, 1899. In 1944 the U.S. Navy Department declared the newly created five-star rank of fleet admiral to be junior to George Dewey's rank.