XML (Extensible Markup Language) is a language used to store textual information in a document format.
XML is written using custom defined tags and looks a bit like HTML. Where HTML consists of predefined tags, in XML you can define your own tags for greater flexibility. An example of XML is:
<?xml version="1.0"?> <book id="583"> <title>Learning XML</title> <author>Erik T. Ray</author> <published> <by>O'Reilly Media</by> <year>2001</year> </published> </book>