Standards-Based Publishing with XML, XSLT, XHTML and XSL-FO 
XML, the Extensible Markup Language recommendation by the W3C, separates content from processing. When you author XML, you describe your information semantically using a computer readable and human readable syntax. The syntax of XML is elements and attributes. We call this semantic markup.
Arbury, Autumn. tekom (2005). Articles>Information Design>XML>Semantic