<), ampersand
(&), etc. are reserved by HTML to represent special
attributes such as the start of HTML elements, graphic characters, and so on.
In addition there are many ISO-Latin 1 characters that you may wish
to include in a document, but which are not trivially available on
a standard keyboard.
HTML allows special referencing to represent these special characters. These are indicated by either character references or entity references.
&),
<.
Note that this number depends on the character set being used -- for example, in some character sets, the 60th character may not be the less than symbol. Thus it is more convenient (and universal) to have a symbolic reference for a character, as opposed to an absolute numeric reference. In HTML (and SGML) such references are called entity references.
&),
<.
Note that, in HTML 2, not all the valid characters have corresponding entity references. In theses cases you may need to use the direct numerical character references. HTML 3 and 3.2 attempted to rectify this by defining a number of additional references, but some of the newer entity references are not understood by all browsers (these newer entity references are shown, in the ISO data table slightly indented and in an italics font. This table also shows the numeric decimal codes for all the ISO Latin-1 characters.
The ISO data table document lists all the ISO Latin-1 characters, alongside their numerical positions in the character set (both decimal -- used by HTML character references, and hexadecimal -- used by URL character encodings) and the corresponding entity reference, if defined.