original url from : http://en.wikipedia.org/wiki/List_of_XML_and_HTML_character_entity_references

The XML specification does not use the term "character entity" or "character entity reference". The XML specification defines five "predefined entities" representing special characters,and requires that all XML processors honor them. The entities can be explicitly declared in a DTD,as well,but if this is done,the replacement text must be the same as the built-in definitions. XML also allows other named entities of any size to be defined on a per-document basis.

The table below lists the five XML predefined entities. The "Name" column mentions the entity's name. The "Character" column shows the character. To render the character,the format&name; is used; for example,& renders as &. The "Unicode code point" column cites the character via standard UCS/Unicode "U+" notation,which shows the character's code point in hexadecimal. The decimal equivalent of the code point is then shown in parentheses. The "Standard" column indicates the first version of XML that includes the entity. The "Description" column cites the character via its canonical UCS/Unicode name,in English.

The HTML 4 DTDs define 252 named entities,references to which act as mnemonic aliases for certain Unicode characters. The HTML 4 specification requires the use of the standard DTDs and does not allow users to define additional entities.

In the table below,the "Standard" column indicates the first version of the HTML DTD that defines the character entity reference. HTML 4.01 does not provide any new character references.