SGML SGML Standard Generalized Markup Language markup document validation An international standard [ISO 8879:1986, Information Processing Text and Office Systems] for the definition of device-independent, system-independent methods of representing texts in electronic form. SGML emphasizes descriptive rather than procedural markup. While HTML is a markup language which deals primarily with the appearance of a document, SGML is a more complex system for describing structural divisions in a text (title page, chapter, scene, stanza), typographical elements (changing typefaces), and other textual features (grammatical structure, etc.). The "tags" in SGML preserve the structure of a text, enable the user to constrain searches to particular structural features of the text and aid in the navigation and use of the text. More information on SGML is available at http://sunsite.berkeley.edu/SGML/. A language for marking up documents so that they could be parsed by computer programs. Each community of people that wishes to author and parse documents must agree on a Document Type Definition (DTD), which it itself a machine-parsable description of what tags a marked-up document must or may have. http://philip.greenspun.com/seia/glossary SGML is the forerunner of both HTML and XML. XML HTML XPath XLink XHTML DOM SAX SVG XPointer Web Services WSDL