- A system is not something presented to the observer, it is something to be recognised by him. Most often the word does not refer to existing things in the real world but rather to a way of organising our thoughts about the real world (Constructivist view)”
- ”A system is anything that is not chaos. (Kenneth Boulding, 1985)”
- ”A system is a structure that has organised components (Churchman, 1979)
- A system is a set of interacting units or elements that form an integrated whole intended to perform some function (Lars Skyttner, 1996).
- A system is the organised collection of men, machines and material required to accomplish a specific purpose and tied together by communication links (Business management).