The word hierarchy – pronounced with the stress on the first syllable, HY-er-ar-ki, IPA: /'haɪ ə ,rɑː,kɪ/ - comes, through Medieval Latin, from the Late Greek ἴεραρχία (hierarchia), a compound noun formed from ἴερεύς (hiereus, priest) and ἀρχή (archē, rule, authority). This etymology would suggest that hierarchy means ‘rule by priests’ or ‘government by the clergy’ - which is indeed one meaning of the word, though by far the least common in contemporary English. The word is also sometimes used nowadays to mean ‘a body of priests or clergy organised in ranks according to their different levels of authority’ (e.g., in the Church of England the body of priests, bishops, and archbishops).
However, the two most common uses of hierarchy in contemporary English have lost the etymological connection with priests and the clergy.
- The word hierarchy may be used to refer collectively to those in authority within an organisation, those in senior positions in an institution, etc., as in ‘The hierarchy have decided that the university will concentrate its research funds on work in the biological sciences’ or ‘Since he became part of the hierarchy he no longer associates with his old colleagues’. (This use of hierarchy is sometimes ironic or slightly contemptuous, carrying the implication that those in authority do not deserve the respect they claim for themselves – because, e.g., they are out-of-touch or too self-satisfied. Compare the expression ‘the top brass’.)
- A hierarchy may be any set of items (whether persons, things, classes, or whatever) arranged in a graded order within a system. Thus in an institutional context a hierarchy is a set of positions within an organisation graded according to their level of authority; in mathematics the set of natural numbers constitutes a hierarchy; and students of the life sciences will be familiar with the Linnaean hierarchy (species, genus, family, order, class, phylum, kingdom) and the hierarchy of life (molecule, macro-molecule, cell, tissue, organ, organ system, organism, population, community, eco-system). Some, though not all, hierarchies may be represented by a diagram of connected nodes with a single element at the top, i.e., a tree structure. See also Word class hierarchy.
A hierarch is a person who occupies a high position within a hierarchy – though the word is most naturally applied to someone holding high rank within a religious hierarchy.