noun
Etymology: Middle English, from Anglo-French amiral commander & Medieval Latin admiralis emir, admirallus admiral, from Arabic amīr-al- commander of the (as in amīr-al-baḥr commander of the sea)
Date: 15th century
the commander in chief of a navy,
2. flag officer , a commissioned officer in the navy or coast guard who ranks above a vice admiral and whose insignia is four stars, flagship , any of several brightly colored nymphalid butterflies