Common term used for linear and nonlinear systems?

Anyone having idea of common term used for separate linear and nonlinear systems?

[Image Analyst]

What do you mean by "common"? Do you mean one term that describes them both? Like, say, "systems"? Or do you mean "commonly used" like one that people use a lot? If so, I don't know of any terms describing such systems that are more common, or better, than "linear systems" and "nonlinear systems".