virtual machine

noun Computers.

1. Also called system virtual machine. a self-contained operating environment that behaves as if it is a separate computer, with no access to the host operating system: When an application runs in a virtual machine, there is little chance that it will damage files or applications in the host system.
2. Also called process virtual machine, application virtual machine. a platform-independent execution environment that itself runs as a normal application inside a host operating system and enables a program written for the virtual machine to execute the same way on any platform: JVM, written in the Java programming language, is the most common process virtual machine.