Extensible Markup Language
An open standard markup language used for Internet applications that is basically a metalanguage used for describing other languages.
While HTML language is limited in its ability to tag and define content within the file, XML is extensible and therefore is not limited in the number of tags that can be applied to descibe the content and how it is to be transferred, displayed or utilized.
This enables data and many of the processes using the data to be automated to a higher level of functionality for real-time data exchange between organizations.
XML is superficially similar to HTML, the primary difference being that the symbols (tags) used in XML can be selected with a larger degree of freedom, while they are fixed in HTML.
This feature allows special forms of XML to be generated for virtually any type of application.
XML is essentially a slimmed-down form of the SGML (Standard Generalized Markup Language) document description language defined in ISO 8879 and was created for transmitting richly structured documents via the World Wide Web.
The International World Wide Web Consortium is responsible for the standardization of XML.