One of the most important aspects of DDEX is that it provides a common language for all music related business transactions. This common language is documented in the "DDEX Data Dictionary".
Rather surprisingly, there are multiple DDEX Data Dictionaries and, although this is counter-intuitive, there is a good reason for this. Also, these "different" dictionaries are all snapshots of the same underlying collection of terms; they are not distinct dictionaries.
DDEX maintains, behind the scenes, one ontology that provides the semantics (i.e. meaning) and syntax (i.e. structure) of all terms and concepts used in all of the DDEX standards. However, each of the DDEX standards only uses a subset of the terms and concepts