View source for Help:Categories

{{Short description|Collections of pages}}
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{{For|more information|Wikipedia:FAQ/Categories}}
{{For|information for [[Wikipedia:Wikipedians|editors]] on how to categorize a page|Help:Category|Wikipedia:Categorization}}
{{Information page|H:CATS}}
{{Reader help}}
'''Categories''' are used in Wikipedia to link articles under a common topic and are found at the bottom of the article page. Clicking the category name displays a list of articles in that category, below a list of sub-categories (''categories'' in that category) (if any). Categories allow readers to navigate through Wikipedia and find related articles.

Categories are not displayed in the [[Help:Mobile access|mobile version]] ([[phab:T24660]]). Mobile users can click "Desktop" at the bottom of a page to see the desktop version with categories. Registered users can enable [[:mw:Reading/Web/Advanced mobile contributions|Advanced mode]] which includes a "Categories" button.

[[File:Chicken Eyeglasses categories.png|center|thumb|900x900px|The bottom of the Wikipedia article [[Chicken eyeglasses]]. At the very bottom of the page, below the References, navigation templates and external links are a series of links. These links are the categories used on the page, which include: [[:Category:Animal welfare]], [[:Category:Animal equipment]], [[:Category:Eyewear]], and [[:Category:Poultry farming]]. By clicking on the category link at the bottom of the page, readers can navigate the Category tree (see below).]]

==Category tree==
All of the categories form a hierarchy, although sub-categories may be a member of more than one category. An example of a small part of this hierarchical structure looks somewhat like this:

{| align = "center"
|
     [[:Category:Main topic classifications]]
                       ↓
               [[:Category:History]]
                       ↓
        [[:Category:History by location]]
                       ↓
        [[:Category:History by country]]
                       ↓
       [[:Category:History of Australia]]
                       ↓
      [[:Category:History of Australia by location]]
                       ↓
 [[:Category:History of Australia by state or territory]]
                       ↓
       New South Wales, Queensland, etc.

|}

The actual relationship is more complex since a category may appear as a subcategory of several other categories. The actual relationship of part of the category structure looks like this:

[[File:Category-diagram.png|border|400px|center]]

The uppermost category in the hierarchy is [[:Category:Contents]]. From here all other categories branch out, including those that are used for the maintenance of Wikipedia.

If an entry in a category is shown in ''italics'' it is a redirect to an article of a different name or a section of an article that contains information about that particular subject.

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{{Wikipedia categorization navbox}}

[[Category:Reader help]]
[[Category:Wikipedia categorization|*]]