noun

1. the commanding officer of a navy or fleet
2. U.S. Navy
   1. an officer of the highest rank, ranking just above a vice admiral and having the insignia of four stars
   2. generally, any of the officers ranking above a captain, with admiral as part of the title of their rank
3. Archaic a vessel carrying the admiral; flagship
4. any of various large, colorful butterflies (genera Limenitis and Vanessa) with unusually small forelegs

Etymology: ME admirail, amirail < OFr admiral, amiral < Ar ʾamīral-ʿālī < ʾamīr, leader + ʿālī, high; sp. infl. by admirable