SGML

The Standard Generalized Markup Language (SGML) is an {{Glossary("ISO")}} specification for defining declarative markup languages.

On the web, {{Glossary("HTML")}} 4, {{Glossary("XHTML")}}, and {{Glossary("XML")}} are popular SGML-based languages. It is worth noting that since its fifth edition, HTML is no longer SGML-based and has its own parsing rules.

See also

• SGML on Wikipedia
• Introduction to SGML