IMS VDEX, which stands for IMS Vocabulary Definition Exchange, is a mark-up language – or grammar – for controlled vocabularies developed by IMS Global as an open specification, with the Final Specification being approved in February 2004.
IMS VDEX allows the exchange and expression of simple machine-readable lists of human language terms, along with information that may assist a human in understanding the meaning of the various terms, i.e. a flat list of values, a hierarchical tree of values, a thesaurus, a taxonomy, a glossary or a dictionary.
Structural a vocabulary has an identifier, title and a list of terms. Each term has a unique key, titles and (optional) descriptions. A term may have nested terms, thus a hierarchical structure can be created. It is possible to define relationships between terms and add custom metadata to terms.
IMS VDEX support multilinguality. All values supposed to be read by a human, i.e. titles, can be defined in one or more languages.
Read more about IMS VDEX: What Is IMS Vocabulary Definition Exchange For?, Technical Details, Implementations