A bureaucracy is a governance system which is based on developing a hierarchy of exclusive personal authority which is held by persons in (mostly non-elected) posts.
Bureaucracies are “top-down hierarchies” because levels of governance tend to get distributed from a person, or small team-- who might or might not be elected-- to increasingly large groups of participations at “lower” levels of governance. In most bureaucracies, the official authority at a specific level of control is assigned to a single individual, or to a team which makes decisions by simple majoritarian process. In addition to their inherently exclusive nature, bureaucracies are highly vulnerable to various risks of corruption, and are often maintained through extensive rules backed by the implicit risk of punishment or expulsion.