What is ranking officer?

In the Navy, the ranks are (in ascending order) Ensign, Junior Lieutenant, Lieutenant, Lieutenant Commander, Commander, Captain, Rear Admiral (lower half), Rear Admiral (upper half), Vice Admiral, Admiral, and Fleet Admiral.

In the Army and Air force, the ranks are (in ascending order) Second Lieutenant, First Lieutenant, Captain, Major, Lieutenant Colonial, Colonial, Brigadier general, Major General, Lieutenant general, General, and general of the army (or air force).