Let's check out wikipida for virtualization definition... skim through the page quickly ... um.. how is that?

Let's me give you the short version:

Virtualization is the core technology that give birth to cloud computing today. Major part of virtualization is software with some hardware assistant to enhance the virtualization performance and capability. Virtualization software basically create abstract layer (emulate) called virtual hardware or virtual machine and serve it to other programs on the computer to use as if it was real hardware. So we can simply assume the virtualization is software based hardware.

Let's me give you a more human explanation

Good imagination of virtualization for human is to think about VR

• VR: technique to lie the human, what you see through the VR head set is not real, it is called Virtual Reality (VR)
• VM: technique to lie the computer (mainly the software), what computer see through hypervisor is not real, it is call Virtual Hardware or Virtual Machine (VM)
• Hypervisor, the very technical term in computer world, is the tool to create the virtual hardware, very common hypervisor widely use in cloud computing industry include KVM, Hyper-v, ESXi. You may already find those term roaming around and now you know they are hypervisor, the virtualization provider in computer world.

Virtualization is mainly software things, with the same hardware if we install different virtualization platform we will get different features, example on the same hardware, hyper-v vs vmware workstation will give you different feature set.