DSDL meaning in Information Technology ?

What is Document Schema Definition Languages mean?

Document Schema Definition Languages (DSDL) is a framework within which multiple validation tasks of different types can be applied to an XML document in order to achieve more complete validation results than just the application of a single technology.

It is specified as a multi-part ISO/IEC Standard, ISO/IEC 19757. It was developed by ISO/IEC JTC1/SC34 (ISO/IEC Joint Technical Committee 1, Subcommittee 34 - Document description and processing languages).

DSDL defines a modular set of specifications for describing the document structures, data types, and data relationships in structured information resources.

Part 2: Regular-grammar-based validation – RELAX NGPart 3: Rule-based validation – SchematronPart 4: Namespace-based Validation Dispatching Language (NVDL)Part 5: Extensible DatatypesPart 7: Character Repertoire Description Language (CREPDL)Part 8: Document Semantics Renaming Language (DSRL)Part 9: Namespace and datatype declaration in Document Type Definitions (DTDs) (Datatype- and namespace-aware DTDs)Part 11: Schema Association reference