What is Centralized Government?

Legal Definition
A centralized government (also centralised government (non-Oxford spelling)) is one in which power or legal authority is exerted or coordinated by a de facto political executive to which federal states, local authorities, and smaller units are considered subject. In a national context, centralization occurs in the transfer of power to a typically sovereign nation state. Menes, an ancient Egyptian pharaoh of the early dynastic period, is credited by classical tradition with having united Upper and Lower Egypt, and as the founder of the first dynasty (Dynasty I), became the first ruler to institute a centralized government.

All constituted governments are, to some degree, necessarily centralized, in the sense that a theoretically federal state exerts an authority or prerogative beyond that of its constituent parts. To the extent that a base unit of society — usually conceived as an individual citizen — vests authority in a larger unit, such as the state or the local community, authority is centralized. The extent to which this ought to occur, and the ways in which centralized government evolves, forms part of social contract theory.

In Mexico the concept is called centralismo.
-- Wikipedia