An SGML entity is an abbreviation for part of a document. Entities subsume the functionality of both programming language macros and programming language include files (external entities).

In HTML, only a limited set of character entity references, such as " are supported. New entities cannot be defined within HTML.

XML supports a limited subset of SGML entity functionality.

Entities are defined with an entity markup declaration which can occur anywhere in the document declaration.

Example

Names for entities must follow the rules for SGML_names.

A reference to an undeclared entity is an error, except if a default entity has been defined. This entity is defined by the entity declaration

External links

• Entity Management in SGML

Entité HTML