A system for annotating a document in a way that is syntactically distinguishable from the text.

"HTML is a markup language used to create web pages, indicating text can be turned into images, tables, links, and other representations."

A system for annotating a document in a way that is syntactically distinguishable from the text, indicating structure and other attributes of the document's content.

"HTML and XML are examples of markup languages, used to structure and define content on the web and in various data interchange formats."