Virtualization is a technology that lets you create multiple virtual machines (VMs) on a single physical hardware. Each VM acts like a separate computer with its own operating system and apps, but they all share the same hardware.
It works by using a software layer called a hypervisor (like VMware ESXi, Microsoft Hyper-V, KVM) that divides physical resources (CPU, memory, storage, network) into virtual parts.
Example: Instead of buying 5 separate servers, you can run 5 VMs on one powerful server → saving cost, space, and power.