For application-specific terms, refer to the help feature of that application.

XHTML

Extensible Hypertext Markup Language. A markup language that is a hybrid between HTML and XML. See HTML, XML, Markup.

XML

Extensible Markup Language. Based on SGML, XML is a specification developed by the W3C. It allows designers to create their own customized tags, enabling the definition, transmission, validation, and interpretation of data between applications and between organizations. See SGML, Markup, SVG, W3C, XHTML.