The table on the right shows what number to use when you want to hide pages that are on your watchlist. See: Wikipedia:Hide Pages in Watchlist for details.
Previously, the Topic namespace was available for the Flow project but it has since been turned off on this wiki.
In addition to subject namespaces, and their corresponding talk pages, there are two virtual namespaces (without corresponding talk pages) for specialist purposes:
You can create a redirect to a Special page, but the redirect will not be followed automatically.
The Media: namespace can be used to link directly to a file, rather than to the file description page.
Aliases and pseudo-namespaces are not namespaces in themselves; their main role is to provide handy ways to link to actual namespaces, by providing shortened links.
Pseudo-namespaces all actually reside in main namespace; but a pseudo-namespace called Transwiki: exists as a pseudo-namespace before being moved to another namespace.
There are six aliases defined for namespaces, all of which are case-insensitive:
A more complete list is available at Wikipedia:Shortcut#List of prefixes.
As with aliases, it is not possible to create a page with a title beginning with an interwiki or interlanguage prefix. It is also not possible to create redirects to interwiki pages, unless it is a soft redirect.
Standard namespace names, aliases and interwiki prefixes are case insensitive. The same applies to the first character after the colon. Hence the following all link to the same page:
The namespace name is a useful variable for searching in and reporting on sets of pages. It is also used to apply features that configure the sets of pages in one namespace differently from another namespace. Using the namespace name MediaWiki can:
The namespace functionality is often visible in the URL, where you will see a namespace number. These are given in the table below.
Random pages are enabled, in the default software configuration, only for the mainspace.
Searching and reporting can operate over the entire database, or they can be limited to a namespace, and so they will offer a list of all the namespaces currently configured. Special:WhatLinksHere also offers a list of namespaces.
All namespaces with a positive number or zero in this list are searchable. Specifically, the Media and Special namespaces are not searchable.
For information on changing the appearance of a page or template by namespace based on CSS, see CSS-based namespace detection on the Meta help page.