Sentence:  A hypervisor is a thin, guest OS—independent Virtualization layer that is loaded onto <WSD>bare metal</WSD>, which interacts with the hardware directly and creates virtual machines in which operating systems, either enlightened or not, can run. <!-- this might be as well interpreted as the sense above; as in, the hypervisor does not run under an operating system. note also the "bare metal hypervisor" citation above --> 
Meaning of the word marked with <WSD> tags:  Physical hardware, as opposed to virtualised.