A 1988 NATO definition is that command and control is the exercise of authority and direction by a properly designated individual over assigned resources in the accomplishment of a common goal. An Australian Defence Force definition, similar to that of NATO, emphasizes that C2 is the system empowering designated personnel to exercise lawful authority and direction over assigned forces for the accomplishment of missions and tasks. The Australian doctrine goes on to state: “The use of agreed terminology and definitions is fundamental to any C2 system and the development of joint doctrine and procedures. The definitions in the following paragraphs have some agreement internationally, although not every potential ally will use the terms with exactly the same meaning.”

A command and control center that is used by a military unit in a deployed location is usually called a “command post”. A warship has a combat information center for tactical control of the ship’s resources, but commanding a fleet or joint operation requires additional space for commanders and staff plus C4I facilities provided on a flagship (e.g., aircraft carriers), sometimes a command ship or upgraded logistics ship such as USS Coronado.