A naval officer of the highest rank; a naval officer of high rank, of which there are different grades. The chief gradations in rank are admiral, vice admiral, and rear admiral. The admiral is the commander in chief of a fleet or of fleets.
- The commander in chief of a fleet.
- A flag officer.
- A commissioned rank in the U.S. Navy or Coast Guard that is above vice admiral and below Admiral of the Fleet.
- One who holds the rank of admiral, Admiral of the Fleet, rear admiral, or vice admiral.
- Any of various brightly colored butterflies of the genera Limenitis and Vanessa.
- Archaic The ship carrying an admiral; flagship.