system of systems

A system built out of other smaller systemsThis is a very generic term for any collection of components that, all together, can do something. Systems can be built from subsystems. Examples are your cell phone; your computer; the radio in your car; anything that seems like a "whole.". Just as you might say that a system could be built out of subsystems, you can also say that separate systems can be combined to create a larger system. They’re just different ways of saying the same thing.