A group of interacting or interrelated entities (called components) that form a unified whole which is:

delineated by its spatial and temporal boundaries
described by its structure and interactions between components
described by its functioning during the evolution or in response to external influence

System consists of components and properties.

The full set of properties existing at the current moment is called a System State.

Description of a System behaviour in response to or correlation with its properties is provided by a System Model.

Depending on whether a System has properties changing over time it can be a Static System or Dynamic System.

The changes of System State may happen as a direct consequence of the time flow or as response to the external factors (represented by Model Inputs in System Model).

See also