I think the term you are looking for is Unitarian or Unitarianism. A unitary government is one that has all the power centralized in one place (e.g. British Parliament, which tells all local governments what they can or can't do.) I hope that answers your question.
A unitary system of government is a type of government where power is centralized. When power is shared between a central government and local governments, this is referred to as a federal system of government.
They are antonyms. Authoritarianism is the belief that the government should have almost all power, and the individuals very little. Libertarianism is the belief that the government should have almost no power, and the individuals very much (though this power is diluted through a large population).