Before we move forward on VMware, it is necessary to know different terminology used with VMware, list of those terminology are mentioned as below

ESXi - Esxi is a thin, embedded version of the ESX server that does not have a servie console. It moves the Server Kernels to a dedicated hardware device.

ISO image - A CD or DVD image that can be downloaded and burnt on a CD-ROM or DVD-ROM or, mounted as a loopback device.

Cluster - A server group in the virtual environment. Clusters enable a high-availability solution. A cluster is a collection of ESX Server hosts and associated virtual machines that share resources and a management interface.

HCL (hardware compatibility list) - The definitive list of hardware that VMware supports.

Host - A computer that uses virtualization software to run virtual machines. Also called the host machine or host computer. The physical computer on which the virtualization (or other) software is installed.

Guest Operating System - An operating system that runs on a virtual machine.

VMware VCenter - A virtual infrastructure management product that manages and provide valuable services for virtual machines and underlying virtualization platforms from a central, secure location.

VMware vSphere client - An interface that allows to connect any windows PC remotely to a vCenter Server or ESX/ESXi.

SAN (storage area network) - A large-capacity network of storage devices that can be shared among multiple VMware ESX server hosts. A SAN is required for VMotion.

Root user - The superuser who has full administrative privileges to log in to an ESX Server host. The root user can manipulate permissions, create users and groups, and work with events.

Virtual Machine - A virtual machine is a software computer that, like a physical computer, runs an operating system and applications. Multiple virtual machines can operate on the same host system concurrently.

VMFS - A clustered file system that stores virtual disks and other files that are used by virtual machines.

Service console - The modified Linux kernel that serves as the management interface to the ESX server.

VMkernel - A kernel that controls the server hardware and schedules virtual machine computations and I/O operations.