Pronunciation: (ad'mur-ul),[key] —n. 1. the commander in chief of a fleet.
2. a naval officer of the highest rank.
3. a naval officer of a high rank: the grades in the U.S. Navy are fleet admiral, admiral, vice-admiral, and rear admiral.
4. Obs.the flagship of an admiral.
5. Brit.a master who directs a fishing fleet.
6. any of several often brightly colored butterflies of the family Nymphalidae, as Vanessa atalanta(red admiral).