This International Standard:

• Specifies an abstract syntax known as the Standard Generalized Markup Language (SGML). The language expresses the description of a document's structure and other attributes, as well as other information that makes the markup interpretable.
• Specifies a reference concrete syntax that binds the abstract syntax to specific characters and numeric values, and criteria for defining variant concrete syntaxes.
• Defines conforming documents in terms of their use of components of the language.
• Defines conforming systems in terms of their ability to process conforming documents and to recognize markup errors in them.
• Specifies how data not defined by this International Standard (such as images, graphics, or formatted text) can be included in a conforming document.