State (country subdivision)

A federated state (which may be referred to as a state, a province, a canton, a Land, etc.) is a territorial and constitutional community forming part of a federation. Such states differ from fully sovereign states, in that they have transferred a portion of their sovereign powers to a federal government. Importantly, when states choose to federate, they lose their standing as persons of international law. Instead, the federal union as a single entity becomes the sovereign state for purposes of international law. A federated state holds administrative jurisdiction over a defined geographic territory and is a form of regional government.

In some cases, a federation is created from a union of political entities, which are either independent, or dependent territories of another sovereign entity (most commonly a colonial power). In other cases, federated states have been created out of the regions of previously unitary states. Once a federal constitution is formed, the rules governing the relationship between federal and regional powers become part of the country's constitutional law and not international law.

In countries with federal constitutions, there is a division of power between the central government and the component states. These entities - states, provinces, cantons, Länder, etc. - are partially self-governing and are afforded a degree of constitutionally guaranteed autonomy that varies substantially from one federation to another. Depending on the form the decentralization of powers takes, a federated state's legislative powers may or may not be overruled or vetoed by the federal government. Laws governing the relationship between federal and regional powers can be amended through the federal constitution and state constitutions.

...
Wikipedia