The term 'Navy Officer' can be abbreviated as ENS (3 letters) and CDR (3 letters). ENS stands for Ensign, which is the lowest rank of commissioned officer in the United States Navy, Coast Guard, Public Health Service Commissioned Corps, and National Oceanic and Atmospheric Administration Commissioned Officer Corps. CDR stands for Commander, which is a senior officer rank in the United States Navy, ranking above a Lieutenant Commander and below a Captain.