Hierarchy
A hierarchy (Greek: hierarchia (ἱεραρχία), from the hierarch, the "chief of the ceremonial") refers to the arrangement of things (objects, names, values, categories, etc.) status "with the arrangement of other things. Abstractly, the mathematical model of a hierarchy is based on the symbolism of the root: the root refers to the upper and vertex at the same level has the same cause. Hierarchy (sometimes abbreviated as HR) links directly to other entities directly or indirectly, either vertically or horizontally.