XML stands for extensible markup language. A markup language is a set of codes, or tags that describes the text in a digital document. XML makes it possible to conduct complex business over the Internet. XML was designed to store and transport data. XML was designed to be self-descriptive – meaning an individual or business will define what tags are used in files that are exchanged within their system.
This is not a tutorial on using or understanding XML. For more information about using XML, see the W3C XML Tutorial.