Definition - What does Power Off mean?
The term "power off" in IT is a variant of several terms used for the idea of stopping the operations of a piece of hardware, not by pulling the power plug, but by using some sort of predetermined control to tell the machine that it is time to stop working. Other variants include the terms "power down," "shut down," "shut off" and "turn off."
Techopedia explains Power Off
The particular etymology of terms like "power off" has advanced along with technology. Over time, the term "shut down" has become the common word choice for discussing these kinds of controls on devices. In some ways, using the terms "power off" or "power down" in IT is like using the alternative terms for the conventional term "turn off" in regard to residential electronics; for instance, in some relatively isolated or rural English-speaking enclaves, locals would use phrases like "cut (the light) off" or even "cut (the light) on," which are more idiomatic than the more conventional use of the verb "turn."
For instance, in IT, someone might suggest "powering off" the computer, instead of saying "turn it off" or "shut it down."
In terms of actual hardware controls, devices may or may not come with elaborate built-in structures that allow for more organized shutdown processes. In many cases, personal computers and other machines are designed to recognize a user event where the power key is pressed down and they do all of the required work themselves. In other cases, devices may come with a warning not to shut them down or power them off without taking specific steps to protect data or hardware components. Modern devices have also been outfitted with other alternatives to a complete power off or shut down, including commands like "sleep" or "hibernate."