Which rank is referred to as O-1 in the U.S. Navy?

In the U.S. Navy, the rank referred to as O-1 is Ensign. This designation indicates the lowest officer rank in the Navy's commissioned officer hierarchy. Officers are categorized into different pay grades, and the "O" in O-1 stands for "officer," while the number signifies the rank's position in the echelon of officer ranks.

Ensigns typically serve as junior officers and are responsible for various tasks including leadership roles, management, and other duties assigned in their specific area of expertise. They often oversee junior enlisted personnel and may also be in charge of a division or a specific operation within a ship or unit.

Understanding this rank is crucial for those entering the Navy, as it reflects the beginning phase of an officer's career and sets the foundation for their advancement and responsibilities in the service.