the commander-in-chief of a fleet or navy
an officer in the Royal Navy or US Navy ranking below an admiral of the fleet or fleet admiral
a senior naval officer of the rank of rear admiral or above
admiralship noun
Middle English via French and medieval Latin from Arabic amīr-al- commander of the (as in amīr-al-baḥr commander of the sea). Early Christian writers understood amīr-al as one word meaning ‘commander’; the original title of an admiral was admiral of the sea or of the navy.