<p><strong>Noun</strong></p><ul><li>the commander in chief of a fleet.</li><li>a naval officer of the highest rank.</li><li>a naval officer of a high rank: the grades in the U.S. Navy are fleet admiral, admiral, vice-admiral, and rear admiral.</li><li>Obsolete: the flagship of an admiral.</li><li>British: a master who directs a fishing fleet.</li><li>any of several often brightly colored butterflies of the family Nymphalidae, as Vanessa atalanta red admiral.</li></ul>