What does the rank O-6 correspond to?

The rank O-6 corresponds to Captain in the military rank structure. In the United States Navy and Coast Guard, an O-6 is a Captain, while in the Army, Air Force, and Marine Corps, it is also referred to as Colonel. This rank is significant as it represents a senior officer role, typically commanding a larger unit or serving in high-level staff positions.

It’s important to understand the rank classification system, where it’s divided into officer ranks designated by "O" for officers, with the number indicating the level. For instance, as ranks increase, so does the number; O-7 would be a Brigadier General in the Army and the equivalent rank in other branches.

In contrast, Lieutenant refers to a lower officer rank (O-1 or O-2 depending on specific details), Admiral (O-7 and above) and Vice Admiral (O-8) correspond to significantly higher ranks within the Navy and coast guard, indicating their higher levels of command and responsibility compared to the rank of Captain.