Last modified on 28 December 2014, at 08:07

Commons:Naming categories

Note: Commons:Categories is the overall category guideline page.
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This page provides guidelines to choose a correct name for a Commons category page. You have to make such choice:

  1. when you create a new category page to categorize media related to a new subject in Commons;
  2. when there are several duplicate categories about the same subject, and you want to choose the correct category to gather media files and subpages in a single category page;
  3. when there is one or several duplicate category(ies) about a given subject, but no correct category name(s), and you want to create a new category page about an existing subject.


Category names should generally be in English (see Commons:Language policy). However there are exceptions:

  • Proper names of individual people, places, buildings, organizations etc. and other specific names of local phenomena, should in general use the name most frequently used in English-language literature. For subjects of only local relevance, proper names in the original language are used generally. However, consensus for global policy isn't achieved yet, so observe current practices and see related discussion pages.
    • Modern personal names are generally not translated
    • Place names widespread in English form are used so (usually countries, capitals, continents, oceans and seas, biggest mountains and mountain ranges and other most known places). Place names of local relevancy (smaller cities, towns, villages, streets, squares, natural feautures) are generally not translated. In some types of names (churches, train stations) the naming usage varies by country. Generally, if the English form of the name is commonly used in English-language texts as stand-alone (not together with the local name as its explanation) and is usually used in English-language maps, it should be used also as the category name.
    • Names of organizations are translated only in some cases. Organization of international relevancy are generally named in English. Abbreviated and acronymic names are generally not translated if the English form is not established. Proper names compound only from common nouns are sometimes translated, sometimes not translated (dependently of their type, relevancy and common and local conventions).
  • For biological taxa, the scientific Latin names should be used (see Commons:WikiProject Tree of Life). However, foods and products derived from biological sources should still use English names, for example, Category:Apples.
  • For some themes, there exists no identical or usable English term, for example Umgebinde, Studentenverbindungen, Légion d'Honneur, Hórreos, Saltimbocca, Vierschaar, Bar mleczny, Smörgåsbord

Original names from non-Latin writing systems are transcribed.

Sadly, We still lack internationalization for category names, but this issue should be resolved with appropriate changes to the MediaWiki software (see bugzilla:29928). Creating intermingled category structures in different languages would only make things worse. Planned connection to Wikidata items seems to be a way to solution.

However, the practical details of this policy are a serious difficulty, so we must bring out some basic principles in order to implement this policy.


Category names use Latin alphabet. Non-English category names from non-Latin writing systems are transcribed to English spelling of Latin alphabet. Names in Latin-derived alphabets are used in original form, including diacritics and additional letter forms. Non-Latin letters are used rarely in some special cases (as symbols, marks etc.).

Grammatical number

Category names that refer to type of objects or group of people should generally be in plural form: Category:Tools, Category:Artists, Category:Lakes, Category:Cephalochordata etc, as opposed to category referring to general theme (Category:History, Category:Weather, Category:Music) or to particular individual object (a person, an organization, a building, a monument, an artwork, an one-shot event etc.).


The Commons categories are an organization system for media files in Wikimedia Commons. The destination of these files is the illustration (act of clarifying or explaining) of Wikipedia articles. So, categories are for Wikimedia Commons what articles are for any Wikipedia. As a result, Commons rules regarding the naming of categories will differ from the matching Wikipedia rules:

  • Names of Commons categories should be optimized for readers over editors; and for a general audience over specialists.
  • Category naming should prefer what the majority of English speakers would most easily recognize, with a reasonable minimum of ambiguity, while at the same time making categorization of media files easy and second nature.
Universality principle

A single name by given subject: we should not use different names to label a single subject. In particular, translations in other languages, or language variants are not an acceptable way to specify subdivisions of the main subject.

Selectivity principle

We should not classify items which are related to different subjects in the same category. Preferably, categories should have unambiguous names. If the name is ambiguous then it is necessary to add a text to the category page in order to specify its unique subject.

Modularity principle

This principle applies to categories which combine two (or more) different criteria. We will call them “compound categories”.


First criterion: to be a church (root category Category:Churches)
Second criterion: to be located in Russia (root category Category:Russia)

The modularity principle asserts that a compound category name is made up from basic names (matching the criteria), which are put together according to a fixed form. These forms are specified in general rules or schemes.


According to Commons:By location category scheme, the pattern, for the category name which matches example 1, is: “[object] in [location name]”.
Therefore, the category name will be Category:[Churches] in [Russia].
Simplicity principle

This principle suggests not to combine too many different criteria. "Compound categories" combining more than three criteria tend to require too many parent categories and become difficult to manage.

Implementation of the principles

We have to realize that Commons Wikimedia project is not a Wikipedia project, and that we have limited competences regarding Encyclopedic matter. Therefore, we should not repeat debates, in Commons, about issues which have been resolved after hard word and sustained discussions in a Wikipedia project.

Which project? Inevitably due to the language policy rule, the English Wikipedia will be the reference for any encyclopedic issue, there is little choice but to use matching English Wikipedia articles as the basis for Commons category names.

However, there are several exceptions where the English Wikipedia article name would not be used:

  • the Wikipedia article name would not appropriately identify the subject of the category. That is the case, in particular, when the subject of the Commons category does not exactly match the subject of the Wikipedia article example?
  • the Wikipedia article name does not comply with the Wikipedia naming conventions
  • the Wikipedia article name is excessively verbose
  • the Wikipedia article name does not comply with a specific Commons rule
  • the Wikipedia article has been renamed (In Commons, we don't move a category each time a matching Wikipedia article is renamed)

In practice, different conventions may have evolved for different parts of Wikimedia Commons. Please see if there exists a category scheme or a commons project for your topic, and follow the conventions described there.

Categories by CRITERION

These are special categories which are useful to group other related pages (not media files) according to a given criterion. They hold only other categories and should be marked with {{MetaCat}} template.

You can choose any appropriate criterion. Many criteria are currently used in Commons, most often used are:

  • by country (nationality, its English Wikipedia variant, is deprecated in Commons)
  • country subdivision, like: by state, by county, by city, by district, etc.
  • by year
  • other time units, like: date, decade, century, etc.
  • People related

For a given criterion, you must associate a set (often a finite set) where you'll pick elements to build the names of the subcategories.

Example Assume (it's not a recommendation) you want to group pictures, which are Category:Spheres, showing spheres of a given color. The associated set is an indefinite list of colors, like red, yellow, green, crimson, periwinkle blue, and so on. The matching categories would be:
  • Category:Red spheres
  • Category:Yellow spheres
  • Category:Green spheres
  • Category:Crimson spheres
  • Category:Periwinkle blue spheres

and they'd be categorized in Category:Spheres by color.

Notice that you must not put a category like Category:Wooden spheres in this group, because wood is a material, not a color (you can find natural wood of different colors, and also cover it to change its natural color).

So, normally, the name of the special category is built as follows:


PARENT CATEGORY can, in some cases, be a special category as well; however it is not recommended to create categories with more than 2 criteria.

Example: Category:Politicians > Category:Politicians by office > Category:Politicians by office by country