Entities are variables that define shortcut names. The parsing process replaces them with common text. You can declare entities either internally or externally.
“General entities” are entities for use within the document content (see Section 4.5.1). The XML Recommendation refers to these entities using the unqualified term “entity.” By comparison, “parameter entities” are parsed entities for use only within the DTD (see Section 4.5.2). General and parameter entities occupy different namespaces; a parameter entity and a general entity with the same name are two distinct entities.
|#DEFAULT value||The attribute's default value.|
|#REQUIRED||Document authors must ...|