How something is; its configuration, attributes, condition, or information content. The state of a system is usually temporary (i.e. it changes with time) and volatile (i.e. it will be lost or reset to some initial state if the system is switched off).
A state may be considered to be a point in some space of all possible states. A simple example is a light, which is either on or off. A complex example is the electrical activation in a human brain while solving a problem.
In computing and related fields, states, as in the light example, are often modelled as being discrete (rather than continuous) and the transition from one state to another is considered to be instantaneous. Another (related) property of a system is the number of possible states it may exhibit. This may be finite or infinite. A common model for a system with a finite number of discrete state is a finite state machine.