A virtualIn our context, refers to what are usually software models of some physical thing. The model behaves like the real thing except, in some cases, in performance. version of a specific piece of hardwareIn this context, "hardware" refers to functions in an IoT device that are built into a silicon chip or some other dedicated component. It's distinct from "software," which refers to instructions running on a processor. – airplane engine, car, etc. – that behaves like and mirrors the true hardware version, keeping in synch with it. Such modelsA simplified representation of something real. We can create models of things in our heads without even realizing we're doing it. Technology often involves models because they let us simplify what would otherwise be extremely detailed, complicated concepts by focusing only on essential elements. can often be used to predict things like wear-out before they happen.