A markup language is an artificial language used to add style information or other metadata to documents. The term markup originates from the way typewritten documents, such as news articles, were marked up with instructions for editing or typesetting.

Most markup languages for documents on the Internet consist of tags that are inserted into the text content of a document. A few of the markup languages for Internet documents are:

• Atom Feed Format
• HTML - Hypertext Markup Language
• RSS - Really Simple Syndication feed format
• SGML - Standard Generalized Markup Language
• XHTML - Extensible HTML
• XML - Extensible Markup Language