Main page: Wikipedia:Administration § Data structure and development
“Articles” belong to the main namespace of Wikipedia pages (also called “article namespace” or simply “mainspace“).
The main namespace, article namespace, or mainspace is the namespace of Wikipedia that contains the encyclopedia proper—that is, where “live” Wikipedia articles reside, as opposed to Sandbox pages.
The main namespace is the default namespace and does not use a prefix in article page names. This is distinct from other namespaces, where page names are always prefixed by an indicator of the particular namespace in which the page resides. For example, all user pages are prefixed by "User:", their talk pages by "User talk:" templates by "Template:" and various types of internal administrative pages by "Wikipedia:" (such as this page). Thus, any page created without such a prefix will automatically be placed in the article namespace.
The main namespace does not include any pages in any of the specified namespaces that are used for particular purposes, such as:
- the talk namespaces for discussing what the content of articles in mainspace should be (for example, Talk:Mathematics)
- the Wikipedia namespace, for material about meta subjects related to Wikipedia and is where policies and guidelines, essays, information, and process pages reside, as well as other “meta” topics about editing Wikipedia (examples, WP:VERIFY and Wikipedia:Statistics);
- the Wikipedia talk namespace, for discussing what the content of pages in Wikipedia space should be, and interpretations of them (for example, Wikipedia talk:VERIFY and Wikipedia talk:Statistics);
- the special namespace, whose pages are created by the software on demand (see Help:Special page);
- the user namespace for pages that are used by individual Wikipedia writers (example, User:Example).
- the file namespace which is used for describing and attributing images (example, File:Great Horned Owl.USFWS.jpg)
- the MediaWiki namespace, which is used to define shortcuts and other text strings used around Wikipedia (example MediaWiki:Wikimedia-copyrightwarning)
But not all pages in the article namespace are considered by all to be articles. Pages in mainspace that are not usually considered articles-proper are:
- the Main Page (a WP:Portal)
- thousands of disambiguation pages, which are used to resolve naming conflicts;
- many millions of redirect pages, including soft redirects, which are used to re-route one page to another page;
Every page in the main namespace can have a companion talk page, and these belong to the “Talk” namespace, i.e., the page names start with the prefix “Talk:”, followed by the name of the page in the main namespace. For example, “Talk:Wikipedia” is the talk page for Wikipedia’s article on itself.