A hierarchy is a type of organization that includes positions of authority, some of which are higher than the other. Some hive based insectoid races, such as the Wirrn, includes queens that are usually seen as higherly significant in the hierarchy.
The Cybermen followed a rigid hierarchy. At the top was the Cyber-Controller, who oversaw Senior Leaders who commanded Major Phalanxes including Leaders, Junior Leaders and the Cyber-Army. (PROSE: Attack of the Cybermen)
The Daleks also had a rigid hierarchy, with the Dalek leaders that were differentiated from normal rank and file daleks by their different coloured casings (usually black or gold). (TV: The Dalek Invasion of Earth, Day of the Daleks, PROSE: War of the Daleks) The highest of the Dalek hierarchy was alternately the Supreme Dalek or the Emperor Dalek. (TV: Remembrance of the Daleks)