The term 'Naval Officer Below Lieut.' is a job description for an Ensign (ENS), which is a commissioned officer in the United States Navy, Coast Guard, Public Health Service Commissioned Corps, and National Oceanic and Atmospheric Administration Commissioned Officer Corps. An Ensign typically holds the rank of O-1, which is the lowest commissioned officer rank in the US Navy. The duties of an Ensign include leading small units of sailors, managing personnel, and providing guidance and instruction to junior officers.