. . "A hierarchy (from the Greek \u1F31\u03B5\u03C1\u03B1\u03C1\u03C7\u03AF\u03B1 hierarchia, \"rule of a high priest\", from \u1F31\u03B5\u03C1\u03AC\u03C1\u03C7\u03B7\u03C2 hierarkhes, \"leader of sacred rites\") is an arrangement of items (objects, names, values, categories, etc.) in which the items are represented as being \"above,\" \"below,\" or \"at the same level as\" one another.A hierarchy (sometimes abbreviated HR) can link entities either directly or indirectly, and either vertically or diagonally."@en . .