What is Hierarchical Organization?

Legal Definition
A hierarchical organization is an organizational structure where every entity in the organization, except one, is subordinate to a single other entity. This arrangement is a form of a hierarchy. In an organization, the hierarchy usually consists of a singular/group of power at the top with subsequent levels of power beneath them. This is the dominant mode of organization among large organizations; most corporations, governments, and organized religions are hierarchical organizations with different levels of management, power or authority. For example, the broad, top-level overview of the general organization of the Catholic Church consists of the Pope, then the Cardinals, then the Archbishops, and so on.

Members of hierarchical organizational structures chiefly communicate with their immediate superior and with their immediate subordinates. Structuring organizations in this way is useful partly because it can reduce the communication overhead by limiting information flow; this is also its major limitation.
-- Wikipedia
Legal Definition
A pyramid like organization when a person controls an area with subordinates. Higher levels are more powerful and control underlings.