XML is a W3C-recommended general-purpose markup language that supports a wide variety of applications.
XML languages or ‘dialects’ may be designed by anyone and may be processed by conforming software. XML is also designed to be reasonably human-legible, and to this end, terseness was not considered essential in its structure. XML is a simplified subset of Standard Generalized Markup Language (SGML). Its primary purpose is to facilitate the sharing of data across different information systems, particularly systems connected via the Internet.
Formally defined languages based on XML (such as RSS, MathML, GraphML, XHTML, Scalable Vector Graphics, MusicXML and thousands of other examples) allow diverse software to reliably understand information formatted and passed in these languages.