Local government is a form of public administration which in a majority of contexts, exists as the lowest tier of administration within a given state. The term is used to contrast with offices at state level, which are referred to as the central government, national government, or (where appropriate) federal government and also to supranational government which deals with governing institutions between states. Local governments generally act within powers delegated to them by legislation or directives of the higher level of government. In federal states, local government generally comprises the third (or sometimes fourth) tier of government, whereas in unitary states, local government usually occupies the second or third tier of government, often with greater powers than higher-level administrative divisions. The question of municipal autonomy is a key question of public administration and governance. The institutions of local government vary greatly between countries, and even where similar arrangements exist, the terminology often varies. Common names for local government entities include state, province, region, department, county, prefecture, district, city, township, town, borough, parish, municipality, shire, village, and local service district.