Explanation:
A Virtual Machine (VM) is a software-based emulation of a physical computer that allows multiple operating systems to run on a single physical machine. It abstracts the underlying hardware and provides an isolated environment for applications.

Virtual machines are managed by a hypervisor, which allocates system resources like CPU, memory, and storage to each virtual machine. They enable hardware virtualization, allowing multiple operating systems to coexist on a single physical server.

VMs provide flexibility, scalability, and security by isolating different applications and environments. They are widely used in cloud computing, software testing, and development.

Formal Definition:
A Virtual Machine (VM) is a software-based abstraction of a physical computer that emulates hardware resources, enabling multiple operating systems to run concurrently on a single physical machine.

Additional Information:
Virtual machines can be categorized as system virtual machines (which run full operating systems) and process virtual machines (which run specific applications).

Popular virtualization platforms include VMware, VirtualBox, and Hyper-V. VMs help optimize hardware utilization and enhance disaster recovery capabilities by allowing quick migration of workloads between physical servers.