Commanding Officer

A commanding officer, abbreviated CO, skipper or ship's captain was a term used to describe one's hierarchical position in relation to others within the same environment. On starships, it was general practice to address the commanding officer as "Captain", regardless of their actual rank or position. Proper naval parlance said that, even if a vessel was commanded by an officer whose rank was lower than captain, that officer was still able to be referred to as a captain while on the deck of their own vessel, no matter their literal commissioned rank.

Military Units
One meaning of commanding officer was the highest-ranking officer and commander of a unit. On starships, the CO usually held the rank of captain, though sometimes a commodore or fleet captain may have also held this position. On starbases, the CO was sometimes referred to as "portmaster" and was usually a flag officer. Some bases, however, were commanded by commodores, captains or commanders.

In rare occasions, the commanding officer needed not be a ranking officer, especially in dire circumstances.

Chain of Command
The term "Commanding Officer" could also be used to refer to the officer whom one directly reported to in the chain of command or in a department. Occasionally, it simply identified an officer of higher rank in comparison to another, or the officer with the most experience if more than one officer held the highest rank at the time, although this was usually referred to as a ranking officer.