In computing, Common Language Runtime (CLR) is an runtime environment enabling the exact same code called intermediate code to run on various computers such as Windows PCs, Unix machines and Macintosheses.
It is the implementation of the Microsoft .NET Common Language Infrastructure. It is the generic multi-language execution engine (a virtual machine) on which code runs, around twenty languages are currently (early 2002) supported. Compilers are defined by the Common Language Specification (CLS), a subset of the CLR which defines interoperability between languages.
See also: Microsoft Intermediate Language and Metadata, Runtime, Java programming language, Virtual machine