ISO 639-2 is a part of the ISO 639 standard that defines codes for the representation of languages. It provides three-letter codes for languages, which help in identifying them in a consistent manner. This standard is widely used in various applications, including libraries, databases, and software development. The codes in ISO 639-2 are divided into two sets: the bibliographic codes, which are used mainly in library catalogs, and the terminology codes, which are more suitable for linguistic and technical purposes. This distinction helps ensure that the appropriate code is used for different contexts.