Name of a Wikipedia article. The wikilink for that article is Salvo_D'Acquisto, and the URL is http://en.wikipedia.org/wiki/Salvo_D'Acquisto.

Every page on Wikipedia has a unique name (a string of characters) which appears in that page's URL and by which it can be wikilinked. Various different forms of the name can be used. In particular, the name as it appears in the URL uses underscore characters where the name displayed in large font as the page header uses spaces. Details of the forms of page names and restrictions on them are given below.

[edit] Namespace and base name

Wikipedia pages which are not articles are prefixed with a "namespace" identifier. For articles, the "basename" is the full page name.

A page name may begin with a namespace prefix – a string (ending with a colon) which the MediaWiki software recognizes as placing a page in a particular namespace. For example, the present page is in the Help namespace. If the name does not begin with any of these recognised prefixes, then it is said to be in the main namespace.

A full pagename therefore takes one of the following forms:

• BaseName (for pages in the main namespace);
• NamespacePrefix:BaseName (for pages in any other namespace).

This full pagename can be generated by the magic word {{FULLPAGENAME}}. The base name (the full name less any namespace prefix) is generated by {{PAGENAME}}. The term "page name" is somewhat ambiguous for pages outside the main namespace, as it may refer to either the full pagename or just the base name, depending on context.

[edit] Invalid page names

For information on how to treat pages whose titles are affected by these limitations, see Wikipedia:Naming conventions (technical restrictions).

In general, a page name is any string of one or more Unicode characters. However, this is subject to certain restrictions. The following are not valid as page titles:

• Base names beginning with a lower-case letter (in any alphabet).^[1]
• Titles containing the characters # < > [ ] | { } (which have special meanings in Wiki syntax), the non-printable ASCII characters 0–31, the "delete" character 127, or HTML character codes such as &amp;.^[2]
• Base names beginning with a colon (:).
• Base names equal to "." or "..", or beginning "./" or "../", or containing "/./" or "/../", or ending "/." or "/..".
• Base names whose length exceeds 255 bytes. Be aware that non-ASCII characters may take up to four bytes in UTF-8 encoding, so the total number of characters you can fit into a title may be less than 255.
• Titles beginning with a namespace alias (WP:, WT:, Project:, Image:). For example, the name Project:A-Kon is not possible.
• Titles beginning with a prefix that refers to another project, including other language Wikipedias, e.g. "fr:" (see Interwiki linking and Interlanguage links). For example, an article about the album "Q: Are We Not Men? A: We Are Devo!" cannot have that exact name, as the "q:" prefix leads to Wikiquote. (The restriction includes the prefixes "w:" and "en:" that refer to English Wikipedia itself.^[3])
• Titles beginning with any non-standard capitalization of a namespace prefix, alias or interwiki/interlanguage prefix, or any of these with a space (underscore) before or after the colon. For example, it is not possible for a title to begin "HELP:", "HeLp:", "Help :" or "Help:_".
• Titles consisting of only a namespace prefix, with nothing after the colon.
• Titles beginning or ending with a space (underscore), or containing two or more consecutive spaces (underscores).

Note also that it is not possible for editors to create page titles beginning with the virtual namespace prefixes Media: and Special:.

[edit] Problematic names

It may be desired to create an encyclopedia article whose title happens to begin with one of the standard namespace prefixes, such as Wikipedia: The Big Adventure or Talk: Secrets are Bad. This is technically possible (although the space after the colon would have to be added with DISPLAYTITLE as described below); however the article would be in the wrong namespace, which would interfere with Search and other functionality. The naming guideline recommends redirecting to an alternative title within mainspace in such situations.

A forward slash ( / ) in the pagename provides special functionality in a namespace where the subpage feature has been enabled. This feature is not active in Wikipedia's main namespace, so a forward slash in an article name has no particular effect (although it may affect the behaviour of the corresponding talk page, as subpages are enabled in talk space).

[edit] Changing the displayed title

It is possible to change the way a page title is displayed at the top of its page. This is done using the magic word DISPLAYTITLE. Under the present software configuration, only limited modifications can be made: the displayed title must still resolve to the true name of the page (i.e. if the displayed title is copied and pasted into a wikilink, the link should point to the original page). This means that DISPLAYTITLE can be used only for such modifications as changing an initial letter to lower case, adding initial colons, changing spaces to underscores, adding a space after a namespace prefix, and adding formatting (italics and bolding).

The syntax for DISPLAYTITLE is {{DISPLAYTITLE:DesiredTitle}}. However it is often applied through a template. Currently available templates are {{lowercase title}}, used on such articles as eBay and iPod, and {{italic title}}, which is used to italicize names of genera and species. (These will work irrespective of where they are placed in the wikitext, but it is normal to place them at the beginning.)

[edit] Alphabetical order

Where page titles are placed in alphabetical order by the system (as at Special:AllPages and on category pages), ASCII-based ordering is used rather than the truly alphabetical ordering that would be expected. For details, see Help:Alphabetical order.

[edit] Spaces, underscores and character coding

In page names, a blank space is equivalent with an underscore. A blank space is displayed in the large font title at the top of the page, while the URLs show an underscore. Wikilinks can use either spaces or underscores (spaces are preferred in article space).

Character codes, such as %41 (which codes "A") and %C3%80 (which codes "À"), are treated in pagenames as equivalent to their corresponding characters. The codes are generally used for most non-alphanumeric and non-ASCII characters in URLs (although the characters themselves may sometimes work as well, depending on browser).

Codes are converted into corresponding characters in link labels: [[%41]] and %C3%80 are rendered as A and À. The URL of the latter page is http://en.wikipedia.org/wiki/%C3%80. It can be disputed whether the "real" name of the page is %C3%80 or À, but in any case there cannot be distinct pages with these names.

In some cases (such as in templates), it is necessary to convert a page name represented by a variable into a form suitable for use in URLs: with underscores for spaces and with % codes for special characters. This can be done using the magic words described below (for full details, see mw:Help:Magic words).

• Certain variables ending with an extra "E" (PAGENAMEE, NAMESPACEE, etc.) return URL-encoded forms. For example, for this page, {{FULLPAGENAMEE}} gives Help:Page_name.
• The localurl and fullurl functions can be used to generate relative and full URLs to a particular page. Fullurl can also be used for interwiki references (but may not work for links to pages on a project with a different $wgScript).

If pagename variables are used within the localurl/fullurl functions, then use standard variables ({{PAGENAME}} etc.) in the first parameter (where they will be encoded anyway), but the "EE" variables ({{PAGENAMEE}} etc.) in the second parameter (the query string), if present. For example:

• {{fullurl:Special:Allpages|namespace=12&from={{PAGENAMEE}}}} gives here:

http://en.wikipedia.org/w/index.php?title=Special:Allpages&namespace=12&from=Page_name

• {{fullurl:Special:Allpages/{{PAGENAME}}|namespace=12}} gives here:

http://en.wikipedia.org/w/index.php?title=Special:Allpages/Page_name&namespace=12

Wrong:

• {{fullurl:Special:Allpages|namespace=12&from={{PAGENAME}}}} gives here:

http://en.wikipedia.org/w/index.php?title=Special:Allpages&namespace=12&from=Page name (wrong link)

• {{fullurl:Special:Allpages/{{PAGENAMEE}}|namespace=12}} gives here:

http://en.wikipedia.org/w/index.php?title=Special:Allpages/Page_name&namespace=12 (works here, the underscore, converted from a space, is not affected by the second conversion, but it does not work with special characters).

[edit] Notes