The term 'Naval Rank' refers to the hierarchical structure of the military, specifically the Navy. The lowest rank is ENSIGN (ENS), which is a three-letter abbreviation for an officer in the Navy or Coast Guard. Ensigns are typically responsible for leading small groups of sailors and managing the day-to-day operations of a ship. SEAMAN (SEAMAN) is a six-letter abbreviation for a sailor in the Navy or Coast Guard. Seamen are responsible for performing various tasks on board a ship, such as maintenance and repairs. Petty Officer (PETTYOFFICER) is a twelve-letter abbreviation for a non-commissioned officer in the Navy or Coast Guard. Petty Officers are responsible for supervising and training enlisted personnel, as well as providing technical expertise. Finally, First Lieutenant (FIRSTLIEUTENANT) is a fifteen-letter abbreviation for an officer in the Navy or Coast Guard. First Lieutenants are responsible for leading divisions of personnel and managing the operations of a ship.