What Does Operating System Virtualization (OS Virtualization) Mean?

Operating system virtualization (OS virtualization) is a server virtualization technology that involves tailoring a standard operating system so that it can run different applications handled by multiple users on a single computer at a time. The operating systems do not interfere with each other even though they are on the same computer.

Techopedia Explains Operating System Virtualization (OS Virtualization)

Operating system virtualization provides application-transparent virtualization to users by decoupling applications from the OS. The OS virtualization technique offers granular control at the application level by facilitating the transparent migration of individual applications. The finer granularity migration offers greater flexibility, resulting in reduced overhead.