## Hierarchy

A containment hierarchy is a hierarchical collection of strictly nested sets. Each entry in the hierarchy designates a set such that the previous entry is a strict superset, and the next entry is a strict subset. For example, all rectangles are quadrilaterals, but not all quadrilaterals are rectangles, and all squares are rectangles, but not all rectangles are squares. ...more on Wikipedia about "Containment hierarchy"

A hierarchical organization is an organization structured in a way such that every entity in the organazation, except one, is subordinate to a single other entity. This is the dominant mode of organization among large organizations; most corporations, governments, and organized religions are hierarchical organizations. ...more on Wikipedia about "Hierarchical organization"

A hierarchy (in Greek: Ιεραρχία, it is derived from ιερός-hieros, sacred, and άρχω-arkho, rule) is a system of ranking and organizing things or people, where each element of the system (except for the top element) is subordinate to a single other element. ...more on Wikipedia about "Hierarchy"

(Hierarchy (mathematics)) * Transitivity — if a is superior to b, and b is superior to c, then a is superior to c; ...more on Wikipedia about "Hierarchy (mathematics)"

Aggregation or Composition relationships in object-oriented design also form a hierarchy, composition hierarchy. ...more on Wikipedia about "Hierarchy (object-oriented programming)"

The hierarchical arrangement of storage in current computer architectures is called the memory hierarchy. Each level of the hierarchy is of higher speed and lower latency, and is of smaller size, than lower levels. ...more on Wikipedia about "Memory hierarchy"

Social hierarchy, a multi-tiered pyramid-like social or functional structure having an apex as the centralization of power. Typically, institutions as businesses, churches, armies and political movements, etc., are structured hierarchically. Commonly, superiors in the apex position, called bosses, have more power than their subordinates at the base of the structure. Thus, the asymmetrical relationship might be one "has power over" others. Some analysts however question whether power "really" works as the standard indicates. See also: chain of command. ...more on Wikipedia about "Social hierarchy"