A virtual machine (VM) is a software emulation of a computer system that allows users to run multiple operating systems or applications on a single physical machine. It enables the creation of isolated and self-contained environments, providing flexibility and efficiency in managing resources. With VMs, users can simulate different computer configurations, test software compatibility, and enhance security by isolating potentially harmful processes. It's like having multiple computers within one physical device, opening up possibilities for efficient resource utilization and versatile computing environments.