The Dictionary of Sociology defines the state thus:
a set of institutions governing a particular territory, with a capacity to make laws regulating the conduct of the people within that territory, and supported by revenue deriving from taxation. The capacity to make and enforce law is dependent on the state's enjoyment of a monopoly of legitimate force. (Abercrombie et al., 2000: 343–4)
It's fair to say that, among sociologists, this definition has wide, but perhaps not universal acceptance.
States are historical phenomena: that's to say they have not always existed. Indeed many societies have, or have had, no state. Tribal societies, for example, typically have no written laws or separate institutions for dealing with, say, education, illness, crime or political decision making: typically ...