ad·mi·ral / ˈadmərəl/ • n. 1. a commander of a fleet or naval squadron, or a naval officer of very high rank. ∎  a commissioned officer of very high rank in the U.S. Navy or Coast Guard, ranking above a vice admiral. ∎ short for vice admiral or rear admiral. 2. a butterfly (subfamilies Limenitidinae and Nymphalinae, family Nymphalidae) that has dark wings with bold colorful markings. See also red admiral, white admiral.DERIVATIVES: ad·mi·ral·ship / -ˌship/ n.

admiral †Saracen ruler or prince XIII–XV; naval commander-in-chief XV. ME. a(d)mira(i)l — (O)F. amiral — medL. a(d)mirālis, etc., f. Arab. amīr commander. See EMIR.
So admiralty XV.