System

Although many definitions have been proposed by various SE groups, I see little to be gained in comparison to standard dictionary1 definitions:

1) A complex unity formed of many often diverse parts subject to a common plan or serving a common purpose;

2) An aggregation or assemblage of objects joined in regular interaction or interdependence: a set of units combined by nature or art2 to form an integral, organic, or organized whole: an orderly working totality: a coherent unification.

Or, we can simply call it the dingus, and be done with it.

Footnotes
  1. Merriam-Webster Unabridged Dictionary for Android, version 3.4.217.26599, 2014.[]
  2. “art” in the sense of “artifact”: a thing produced by humans.[]