What is Common Language Specification(CLS)?

CLS:-

Common Language Specification (CLS) is a set of basic language features that .Net Languages needed to develop Applications and Services,which are compatible with the .Net Framework. When there is a situation to communicate Objects written in different .Net Complaint languages, those objects must expose the features that are common to all the languages.Common Language Specification (CLS) ensures complete interoperability among applications, regardless of the language used to create the application.