Wikipedia:What is an article

Wikipedia:FAQ

A Wikipedia article is defined as a page that has encyclopedic or almanac-like information on it ("almanac-like" being; lists, timelines, tables or charts).

This does not include any pages in any of the specified namespaces that are used for particular purposes, such as:

the Wikipedia namespace for material about meta subjects related to Wikipedia (example, Wikipedia:Statistics and its talk page, Wikipedia talk:Statistics);
the talk namespace for discussing what the content of pages should be (for example, Talk:Mathematics)
the special namespace, whose pages are created by the software on demand (example, Special:Recent Changes);
the user namespace for pages that are used by individual Wikipedia writers (example, User:Larry Sanger).
any of the image namespaces which are used for describing and attributing images (example, :Image:Great Horned Owl.USFWS-thumb.jpg)

These namespaces have a yellow background color to distinguish them from pages in the article namespace which have white backgrounds.

There are many non-articles in the article namespace; most notably:

the Main Page;
thousands of very short "stub" pages that may not be considered real articles yet (defined by articles not containing a link);
thousands of disambiguation pages which are used to resolve naming conflicts;
thousands of "redirect" pages which are used to re-route one page to another page.

The automatic definition used by the software is that any page that is in the article namespace, is not a redirect page and contains at least one wiki link is counted as an article. The software currently has no method of detecting disambiguation pages.