organised community living under a system of government; either a sovereign state, constituent state, or federated state
A state is a polity under a system of governance. There is no undisputed definition of a state. A widely used definition from the German sociologist Max Weber is that a "state" is a polity that maintains a monopoly on the legitimate use of violence, although other definitions are not uncommon.Some states are sovereign (known as sovereign states), while others are subject to external sovereignty or hegemony, wherein supreme authority lies in another state. The term "state" also applies to federated states that are members of a federation, in which sovereignty is shared between member states and a federal body.
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. In British and Commonwealth English, "state" is the only term that has that meaning, while "the government" instead refers to the ministers and officials who set the political policy for the territory, something that speakers of American English refer to as "the administration".
Many human societies have been governed by states for millennia; however, for most of prehistory people lived in stateless societies. The first states arose about 5,500 years ago in conjunction with rapid growth of cities, invention of writing and codification of new forms of religion. Over time, a variety of different forms developed, employing a variety of justifications for their existence (such as divine right, the theory of the social contract, etc.). Today, the modern nation state is the predominant form of state to which people are subject.
Read more or edit on Wikipedia