Virtualization: Virtualization is the ability to run multiple virtual machines on a single piece of hardware. The hardware runs software that enables you to install multiple operating systems capable of running simultaneously and independently, in their own secure environment, with minimal impact on performance. Each virtual machine has its own virtual CPU, network interfaces, storage, and operating system.
Hypervisor: A hypervisor, also called a virtual machine manager, is a program that allows multiple operating systems to share a single hardware host. Each operating system appears to have the host’s processor and memory, and other resources all to itself. However, the hypervisor is actually controlling the host processor and resources, allocating what is needed to each operating system in turn and making sure that the guest operating systems (called virtual machines) cannot disrupt each other.
Oracle VM Server: A self-contained virtualization environment designed to provide a lightweight, secure, server-based platform for running virtual machines. Oracle VM Server is based on open source technology (Xen hypervisor for example) tailored by Oracle, and includes Oracle VM Agent to communicate with Oracle VM Manager for management of virtual machines. Oracle VM Server is installed on bare metal server hardware.