Virtual Machine. A software-based emulation of a physical computer, allowing you to run multiple operating systems on a single hardware platform. Think of it as a computer within a computer, where you can install software, run applications, and perform tasks just like you would on a physical machine—without the need for extra hardware. Virtual machines are perfect for testing, development, or running legacy software without messing with your main setup. They provide flexibility and efficiency, making it easy to switch gears without any heavy lifting.