To dumb down "operating system" for normies, they're probably going to say something along the lines of "the software that makes your computer work.. like Windows." If it stays at that level, we'll have a specific, discrete definition in play.
A broader, equally correct definition could be "the software that makes technology work.. there's an operating system on your computer, your cell phone, your Alexa, and even your car." Then yes, some people will think of their Ring doorbell, the cash register at the coffee shop, and other embedded systems, even if they've never heard the word "embedded."
The definition that shows up will depend entirely on a) the context of the case and b) the savviness of the attorneys involved.
Not a bet I want to take.