XML, Web Services, and the Data Revolution

By Frank  P.  Coyle

This section is meant to provide a short, high-level overview of XML. For a more detailed treatment of XML see the references at the end of this appendix.

XML stands for "Extensible Markup Language," a language developed by the World Wide Web Consortium (W3C). It is considered a meta language because it is used to define other languages through the use of markup tags, which add structure and meaning to documents. While XML markup tags look like HTML tags, they allow designers to describe the content rather than the format of the text they enclose. When describing data, developers are free to name their tags in whatever way best describes their content. This flexibility is what makes XML an extensible language.