Hierarchy is a natural structure of any social species. In human societies, hierarchies could be formal or informal, where a formal hierarchy is based upon position in society, like profession, occupied post, etc., whereas the informal hierarchy is the social position between people of formally equal level.
While the formal hierarchy structure is accepted or at least respected by almost every member of a specific society (most people perceive a country leader, even an incompetent one, as a figure to be respected), in informal hierarchies the struggle for a higher position is more or less constant.
In formal hierarchies, like in companies or other organizations, the positions could be referred as ranking.
