 In a military context, a command is a collection of units and formations under the control of a single officer.Although during the Second World War a Command was also a name given to a battle group in the US Army, in general it is an administrative and executive strategic headquarters which is responsible to the national government or the national military headquarters.It is not uncommon for a nation's services to each consist of their own command (such as Land Component, Air Component, Naval Component, and Medical Component in the Belgian Army), but this does not preclude the existence of commands which are not service-based.