Definition of XML

 

Extensible Markup Language, abbreviated XML, describes a class of data objects called XML documents and partially describes the behavior of computer programs which process them. XML is an application profile or restricted form of SGML, the Standard Generalized Markup Language [ISO 8879]. By construction, XML documents are conforming SGML documents.

 
 -- Extensible Markup Language (XML) 1.0 (Third Edition) W3C Recommendation 04 February 2004