the department in charge of the navy (as in Great Britain)
"After serving for twenty years, he retired from the Admiralty to take a quieter job as a maritime historian."
the office of admiral
"The new maritime regulations were drafted directly under the supervision of the Admiralty before being sent to parliament for approval."
The office or jurisdiction of an admiral.
"The court ruled that the dispute fell under admiralty law because it involved a collision between two ships on international waters."