A state is a type of polity that is an organized political community living under a single system of government. States may or may not be sovereign. For instance, federated states are members of a federal union, and may have only partial sovereignty, but are, nonetheless, states. Some states are subject to external sovereignty or hegemony, in which ultimate sovereignty lies in another state. States that are sovereign are known as sovereign states.
The term "state" can also refer to the secular branches of government within a state, often as a manner of contrasting them with churches and civilian institutions.
Speakers of American English often use the terms state and government as synonyms, with both words referring to an organized political group that exercises authority over a particular territory.
Many human societies have been governed by states for millennia, but many have been stateless societies. Over time a variety of different forms developed, employing a variety of justifications of legitimacy for their existence (such as the divine right of kings, the theory of social contract, etc.). In the 21st century, the modern nation-state is the predominant form of state to which people are subjected.
There is no academic consensus on the most appropriate definition of the state. The term "state" refers to a set of different, but interrelated and often overlapping, theories about a certain range of political phenomena. The act of defining the term can be seen as part of an ideological conflict, because different definitions lead to different theories of state function, and as a result validate different political strategies. According to Jeffrey and Painter, "if we define the 'essence' of the state in one place or era, we are liable to find that in another time or space something which is also understood to be a state has different 'essential' characteristics"