Wikidata:Glossary
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This glossary defines important Wikidata concepts and refers to more detailed information. SeeWikidata:Introduction for a general introduction into Wikidata and theglossary guidelines for how to write and improve glossary entries.
| Glossary |
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| Alias is an alternative name for anitem or aproperty. In the user interface, it is sometimes labeled as "Also known as". The usual or most important name is thelabel. Aliases help people find an item even if they don’t search with the label. For example, the itemQ2 has the label “Earth” and aliases such as “Tellus” and “Blue Planet”. It's a type ofterm. Further information:Help:Aliases |
| Article placeholder is an extension to display stub articles and to start Wikipedia articles based on aview of Wikidata items. Seemw:Extension:ArticlePlaceholder. |
| Abadge is an optional marker that can be attached to asitelink to another Wikimedia page. For instance, a sitelink can be marked to link to a "featured article" or to a "proofread" page. Further information:Help:Badges |
| Category item,template item, andmodule item are Wikidata items withsitelinks to categories, templates, or modules on Wikimedia sites. When the last sitelink is deleted, these items are generally deleted (seeWikidata:Database reports/to delete). |
| Claim is a piece of data about theentity on thepage where the claim appears. A claim consists of aproperty (such aslocation) and either avalue (e.g.,Germany) or one of the special cases "no value" and "unknown value". A claim can havequalifiers, such as temporal qualifiers saying that the claim is valid within a specific time frame. Compared totriples in the RDF data model, a claim uses a property to express the predicate of a triple and a value to express the object of a triple. Claims form part ofstatements onitem pages, where they can be augmented withreferences andranks. They can also occur on non-item data pages. |
| Commons (orWikimedia Commons) is a Wikimedia project to store images, audio, video and other files. Wikibase includes three differentdatatypes to link from Wikidata to media files, geographic shapes and tabular data. Commons is adding statements to files asmediaentities. |
| Completeness is an assessment of available data with a measure for coverage. At Wikidata the presence of an item or statement does not imply that all similar items or statements are present. Wikibase does not include any completeness indicator.Quantity properties can be used to compare with available statements or items. Example: The item about states of the USA has a statement with quantity 50. One can compare that with the count of uses of the item. A few tools attempt to measure completeness. To some extent,property suggester andsuggestion constraints indicate elements missing to complete items. |
| Complex constraint (orcustom constraint) is aconstraint defined by a freely chosen SPARQL query in a template on a property talk page. Further information:Template:Complex constraint |
| Conflation is a type of error, usually on an item, where aspects of several distinct concepts are mixed together. For example, an item with the date of birth of one person and the occupation of another person with the same name. Further information:Help:Conflation |
| Constraint is a rule for how a particularproperty should be used. For instance most identifiers should have only one value, so there is asingle value constraint on them. A special kind are calledcomplex constraints. Further information:Help:Constraints |
| Constraint report can refer to a series of periodically updated pages for each property based onconstraints or aspecial page for an individual item or other entity. Further information:Wikidata:Database reports/Constraint violations |
| Cradle is anediting tool to create new Wikidata items based on a form with predefinedproperties andvalues. Further information:Wikidata:Cradle |
| Datatype (orpropertyType) is an attribute of aproperty specifying the type and shape of thevalue in eachclaim. Eachproperty is assigned a pre-defined datatype, whichusually can not be changed. Not all values can be linked, as long as there are certain datatypes missing. Data types can only be defined by developers. See alsoSpecial:ListDatatypes for currently available datatypes. Data type does not directly specify how values are stored internally; this is specified byvalue type. Further information:Help:Data type |
| Data namespaces arenamespaces forpages that hold Wikidata entities. The data namespaces in Wikidata are themain namespace for the Wikidataitems, "Property:" forproperties, and "Lexeme:" forlexemes. Further information:Help:Namespaces |
| Date (ortime ortimeValue) is adatatype for property values. It allows to enter dates in different precisions and enables date calculations in queries. Hour or minute precision isn't supported. TheWikidata property for the date of foundation has such values. Further information:Help:Dates |
| Description is a language-specific descriptive phrase for anitem orproperty. It provides context for thelabel. For example, there are several items about places and other things with the label "Dakar":Items with the label Dakar in English (query). The description therefore does not need to be unique, neither within a language or Wikidata in general, but it must be unique together with thelabel. Uniqueness for a combination of a label and a description is strictly enforced. If your edit does not meet this requirement you cannot publish it. It's a type ofterm. Further information:Help:Description |
| Disambiguation item is a Wikidata item withsitelinks to disambiguation pages. This is its only purpose. Generally, it has a claim withinstance of=Wikimedia disambiguation page. Further information:Wikidata:WikiProject Disambiguation pages See also:#Conflation |
| Duplicate is anentity, generally an item, about the same concept as another entity. Duplicates are usuallymerged creating aredirecting entity. Special types of duplicates aretemporary duplicates,permanent duplicates, andtrue duplicates. |
| Editing interface is aview that allows to add or modify data. These views are the default view, the Commons structured data interface, Wikidata bridge, and a series of API-based tools, notablyQuickStatements,Cradle, PetScan, OpenRefine or thePywikibot framework. |
Entity is the content of a Wikidatapage (or part of a page in the case ofsubentities) in one of thedata namespaces, such as anitem (in themain namespace),property (in the Property namespace) orlexeme (in Lexeme namespace). Every entity is uniquely identified by anentity ID, which is a number with a prefix; for example, starting with the prefixQ for an item andP for a property. Entity IDs of subentities are formed differently, seeform andsense. An entity is also identified by a unique combination oflabel anddescription in each language. An entity may have alternatealiases in multiple languages (something similar to synonyms). Each entity has also adereferenceable URI that follows the patternhttp://www.wikidata.org/entity/ID whereID is its entity ID.Otherextensions may define new types of entities. For example:
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| Entity selector allows picking anentity by entering part of its name and selecting it from a list of search results. For items, the results are based on the labels and aliases. Thedescription is displayed, if there is one. Example: type "human" to pickQ1156970 from "human (Q5) common name of Homo sapiens", "humanity (Q1156970) total world population of human", etc. This is different from theProperty Suggester. Further information:Help:Suggesters and selectors |
| EntitySchema is a special type of Wikidatapage containing a document inShEx format, and related metadata. Although it may have labels, descriptions and aliases similar to items, it isnot a type ofentity. Entities may be validated against an EntitySchema using theShEx2 — Simple Online Validator tool. Further information:Wikidata:Schemas Further information:Wikidata:WikiProject Schemas |
| External identifier is a type of property — a string used in the database of external organizations. Some properties have external identifiers as values. Theyuniquely identify an item, although the uniqueness is not enforced by software, but controlled byconstraint. For example, an ISBN for a book or the unique part of the URL of a movie or an actor in the Internet Movie Database. |
| Federation query is aquery through a service available onQuery Server allowing to access databases other than Wikidata. Further information:Wikidata:SPARQL federation input |
| Form is a string of characters that occurs in a particular grammatical context for alexeme. Every Lexeme may have multiple forms. Forms are identified on each lexeme by theLexeme ID followed by a hyphen, the letter "F" and a number. Forms may have statements just as other entities do. They are also assignedgrammatical features such as "plural" for Form L1298-F2 ("forms"). A form is a type of anentity. Further information:Wikidata:Lexicographical data/Glossary |
| Historic information is included by qualifying it with adate. If information is no longer current, date qualifiers are added instead of statements overwritten. Historic information is different fromincorrect information. |
| Human (orinstance of human) is a Wikidata item about a person or an individual. It has a claim withinstance of=human. |
| Incorrect information is a claim supported by a reference, but generally considered invalid or inaccurate. While Wikipedia usually excludes such information, Wikidata's deprecatedrank allows to flag such statements. This helps avoid a situation in which it's deleted and erroneously re-added as valid information. Incorrect information is different fromhistoric information. |
| Instance of,subclass of, andhas part (alsoclass ortype) are used on Wikidata to refer to the propertiesinstance of,subclass of,has part(s), and a few other related ontological properties, their values, or items using them. Further information:Help:Basic membership properties |
| Item refers to a real-world object, concept, or event that is given an identifier in Wikidata together with information about it. Each item has a correspondingwiki page in the Wikidatamain namespace. That page'stitle is the item's unique prefixedid, such as Q42. Every item may have human-readablelabels anddescriptions in multiple languages, but they are not necessarily unique. Items may also havealiases to ease lookup. The main data part of an item is the list ofstatements about the item. An item can be viewed as the subject-part of atriple inlinked data. An item is a type of anentity. Further information:Help:Items |
| Item identifier: seeQID below. |
| Label is the main name given to anitem or aproperty. E.g. the item with theitem identifierQ7378 has the English label “elephant”. An entity may have one label in each given human language. Labels do not need to be unique.Descriptions andaliases are used to distinguish between entities with the same label. A label of aWikidatapage is automatically displayed in the user interface language in front of itsid (e.g. "elephant(Q7378)"). A label doesnot uniquely identify the page; this function is served by itsQID(title) only. The label is a type ofterm. In English, labels should generally follow the English languagecapitalization rules: uppercase should only be used inproper nouns. Further information:Help:Labels |
| Lag ordatabase lag at Wikidata is a delay in the update of data on other projects orQuery Server. |
| Language attributes are the language-specificlabels,aliases anddescriptions that are assigned toitems,properties andqueries. These are human-readable text to improve understanding of the scope of the item; for example, the specific type of real world entity. If they are missing, some of them can be replaced by strings from alternate languages, following thelanguage fallback chains. |
| Language code is an identifier for the language of a label, description, alias, or monolingual text value. The language codes for labels, descriptions, and aliases are shared with other Wikimedia projects. More codes for monolingual text are defined specifically for Wikidata. Lexemes use some of these, as well as some additional codes or items to identify the language in lemma, gloss, and form. A language code is also assigned to sitelinks. Codes are based mostly onIETF language tags. Further information:Help:Monolingual text languages |
| Language fallbacks (alsolanguage chains) are methods to systematically replace missinglanguage attributes with strings from alternate languages. The exact replacement rules can be chosen depending on the type of page, whether the user is logged in, or the user preferred languages. |
| Lexeme is anentity ofLexicographical data. A lexeme may contain sense and form entities, but no sitelinks. Instead of a label, a description, and aliases, lexeme entities have a lemma (possibly more than one, for languages with spelling variants), a language, and a lexical category. Further information:Wikidata:Lexicographical data/Glossary |
| LID (orL number) is the identifier for alexemeentity in Wikidata, comprising the letter "L" followed by one or more digits. |
| Listeria (orWikidata list) is a tool toshow data from Wikidata in list form at Wikimedia projects. Data is periodically updated by bot. Further information:Template:Wikidata list |
| Mainspace is one of thenamespaces in a wiki. Namespaces in Wikidata other than the mainspace have prefixes. In Wikidata, the mainspace contains the pages with theitems. Further information:Help:Namespaces |
| MediaWiki is the software that runsWikidata, Wikipedia and otherwikis. The MediaWiki installation of Wikidata makes use of theWikibase extension. Further information:mw:Special:MyLanguage/Manual:What is MediaWiki? |
| MediaInfo is a type ofentity used to describe files. It's activated on Wikimedia Commons. |
| Meta pages These are all the pages that are notentities, which means that they do not belong to thedata namespaces. Wikidata meta pages contain unstructured content in wikitext, including Wikidataclient sideinclusion code. Examples aretalk pages,category pages,project pages (in the Wikidata namespace) andhelp pages (in the Help namespace). Meta pages also comprise content and data automatically generated by the MediaWiki software (for example, the edit history of apage, orspecial pages). |
| Name item is a Wikidata item about a given name or a family name. Such items are used as values forfamily name orgiven name and can include additional information and sitelinks. Further information:Wikidata:WikiProject Names |
Namespaces are a kind of category for pages in a wiki. For each namespace you may have different rules about the pages and their content. In Wikidata, the most important namespace (or ‘main namespace’) is for the Wikidataitems. The URL of a Wikidata mainspace page ends with aQ and a number, for example,Q7378 for “Elephant”. The pages in other namespaces start with the namespace name, the “prefix”. For example, help pages start with “Help:”, such asHelp:Contents.Further information:Help:Namespaces |
| Object: SeeSubject |
| Page is an internal or external webpage with a uniquetitle, for example, anarticle in Wikipedia main namespace or anitem in Wikidata main namespace. A page is a part of a site. In Wikidata, the term "page" may refer to anitem or aproperty page in thedata namespaces, to ameta page in other namespaces, or to an externallinked page on Wikipedia, another Wikimedia site, or an external site. A page on a client site may be referenced using asitelink. Pages in the main namespace of Wikidata containitems, and one page can only hold one item. |
| Predicate: SeeSubject |
| Prefix Used in thequery service. Further information:mw:Wikibase/Indexing/RDF Dump Format/Prefixes Further information:EntitySchema:E49 |
| Project is a term often used in theWikimedia movement to refer to a Wikimediawiki. In Wikidata, the term usually refers toWikidata itself. |
| Property describes the data value of astatement and can be thought of as a category of data, for example, "color" for the data value "blue". Properties, when paired withvalues, form a statement in Wikidata. Properties are also used inqualifiers. Properties have their own pages on Wikidata and are connected toitems, resulting in a linked data structure. A property is a type of anentity Further information:Help:Properties |
| Property suggester provides a preselection ofproperties when adding statements to Wikidata items. These are based on the frequency of the properties on similar items. Example: on an item withinstance of=human only, suggestions could besex or gender,occupation,date of birth. These may or may not be appropriate for the specific item. This is different fromentity selector andsuggestion constraints. Further information:Help:Suggesters and selectors |
| QID (orQ number) is theunique identifier of a dataitem on Wikidata, comprising the letter "Q" followed by one or more digits. It is used to help people and machines understand the difference between items with the same or similar names. For example, there are several places in the world called London and many people called James Smith. This number appears next to thelabel at the top of each Wikidata item. |
| Qualifier is a part of theclaim that says something about the specific claim, often in a descriptive way. A qualifier might be a term according to a specific vocabulary but can also be a variant descriptive phrase (whether those terms or phrases are free text or part of some vocabulary would probably be up to the Wikidata community). Further information:Help:Qualifiers |
| Quantity (incorrectlynumber) is adatatype for property values. It allows to enter integers or decimal numbers. Optionally aunit or a bound can be included. TheWikidata property for population has such values. Numeric identifiers are not quantities, butexternal identifiers. Further information:Help:Data type#Quantity |
| Query is a search acrossitems in Wikidata and their associated data. Queries are usually executed on theWikidata Query Service using the SPARQL query language. Further information:Wikidata:SPARQL query service/Wikidata Query Help |
| QuickStatements (QS) is a third-party tool that can edit Wikidata items, based on a simple set of text commands. The tool can add and remove statements, labels, descriptions, and aliases. It can also add statements with optional qualifiers and sources. Further information:Help:QuickStatements |
| Rank is a quality factor used for simple selection and filtering in cases where there are severalstatements for a given property. In such cases, you may want to indicate which statement is more important or relevant than other statements. By default, a statement has the rank "normal", but you can change this to either "preferred" or "deprecated". "deprecated" rank can be used for statements supported by a reference, but considered incorrect. Further information:Help:Ranking |
| Redirecting entity (orredirect) is anitem or alexeme that redirects to another item or lexeme (target). As in many uses these would need to be queried specifically, a bot usually replaces redirects used as values with their target. Further information:Help:Redirects |
| AReference (orsource) is used to point to a specific resource that supports aclaim inWikidata. A reference can be a link to a URL or anitem; for example, an item about a book. Wikidata does not aim to answer the question of whether a claim is correct, but only whether the claim appears in a reference. A claim together with the reference form astatement. Further information:Help:Sources |
| Repurposing is changing the definition or scope of anentity, in general an item, by editing its label, description or statements. Generally to be avoided. |
| Sandbox orsandbox items are series of items, properties and other entities at Wikidata to test features within the Wikidata live database. Examples: itemQ4115189, propertyProperty:P369, EntitySchemaEntitySchema:E123, lexemeLexeme:L123. |
| Sense refers to a specific meaning for alexeme. Senses are identified on each lexeme by theLexeme ID followed by a hyphen, the letter "S" and a number. Senses may have statements just as other entities do. They also allow a "gloss": a free-form description of the meaning (one per language). A sense is a type of anentity. Further information:Wikidata:Lexicographical data/Glossary |
Site is a reference to an external website in general, but insitelinks it refers to specific registered wikis, for example, a Wikipedia language version. Those sites are referenced by site identifiers, or for shortsiteids, technically corresponding to the wiki'sDBname. For example, the Latin Wikipedia's siteid islawiki. Each externalpage can have only one link registered in Wikidata and oneitem can only have one link to each external site. |
| Sitelink is an identification of a linked page on another site. It consists of asite identifier and atitle, and is stored in individualitems in Wikidata. Sitelinks are used both for identifying an item from an external site, and as a central storage of interlanguage links (sometimes known as "interwiki links", although this term also has a different meaning). Further information:Help:Sitelinks |
| Sitelinks between Wiktionary editions are generally not provided through Wikidata, but another function. Further information:Wikidata:Wiktionary/Sitelinks |
| Snak is a technical term ofWikibase software. Data users are most likely to encounter it whenaccessing Wikidata through the MediaWiki API. It refers to the combination of aproperty and either avalue or one of the special cases "no value" and "unknown value". Snaks can be found inclaims (then they are calledmain snaks) or inqualifiers as part ofstatements (then they are calledqualifier snaks). E.g., in the statement "Emma Watson was a cast member ofHarry Potter and the Philosopher's Stone in the role of Hermione Granger" there is a main snak "was a cast member of Harry Potter and the Philosopher's Stone" and a qualifier snak "in the role of Hermione Granger". |
| AStatement is a piece of data about anitem, recorded on the item'spage. A statement consists of aclaim (a property-value pair such as "Location: Germany", together with optional qualifiers), augmented byreferences (giving the source for the claim) and arank (used to distinguish between several claims containing the same property; "normal" by default). Wikidata makes no assumptions about the correctness of statements, but merely collects and reports them with areference to a source. The term "statement" is often used interchangeably with "claim", but technically it only becomes a statement once at least one reference has been added. Further information:Help:Statements |
String (alsocharacter string) is a general term for a sequence of freely chosen characters interpreted as text like "Hello", as opposed to a value interpreted as a numerical value (like 3.14) or a link to an item (like[[Q1234]]). In addition to a stringdatatype, Wikidata supports language-specific texts using "monolingual-text" as thevalue of a property. |
| Subject,predicate andobject are terms sometimes used to describe aclaim when viewingentity,property andvalue as atriple. |
| Suggestion constraint is a status of a propertyconstraint that provides suggestions of additional improvements. This can be statements with other properties to be added to the item. |
| Term is a part ofentity, includeslabel,description andalias. Terms may only be plain text, which means that they cannot contain any wiki markup. |
| Termbox is the zone at the top of an item page, which includes the labels, the descriptions, and the aliases in different languages. |
Title is the name of apage. All pages must have a unique title within a givenwiki, as the title is included in the URL for the page. For example, there can be only one page with the title "Douglas Adams" on English Wikipedia. In Wikidata, a title is either anentity identifier such asQ42, or it starts with anamespace prefix such asHelp:. The page title is not to be confused with thelabel for a Wikidata item or property. Wikidataitems are connected to pages on otherWikimedia wikis viasitelinks, which use the page's title to uniquely identify the resource. |
| Triple (or "semantic triple", or "triplet") is the atomic data entity in the RDF data model, which codifies statements in the form of subject–predicate–object expressions. |
| Unit is a Wikidata item used with aquantity-value. Frequently used units are metre or EUR, but any item could be used as unit. If the unit includes aconversion to SI unit statement, quantities with the unit are normalized based on that. Seemw:Wikibase/Indexing/RDF Dump Format#Normalized values. |
| Value (alsodatavalue) is the actual piece of information stored within aclaim. Wikidata has a range of alloweddatatypes, such as "item", "mathematical expression", and "quantity". The datatype needed for any given claim is determined by the property used (e.g. the value in a "place of birth" claim must be an "item"). Instead of a normal value, you can also use one of the special cases "no value" or "unknown value" in a claim. Further information:Help:Statements |
| Value type is the wayvalues are stored internally. Eachdata type corresponds to one value type. For example, although external identifier, Commons media and mathematical expression are different datatypes, they all use the "string" value type. Values for some data types contain multiple parts with different value types. For example, a quantity contains four parts: "amount", "unit", "upperbound" and "lowerbound", the last two being optional. Unit is a URL which points to a Wikidata item; the other three parts are numbers in string (not floating-point number). |
| View is a way data can be visualized or accessed. Besides the default view, Wikibase offers views for mobile devices, as well as for rdf and json formats. The data can be accessed with an API. Data on Wikidata is mirrored onWikidata Query Server offering various result views. Some of the views areediting views, others not. Examples of tools and extensions that provide custom views areReasonator,Article Placeholder, andListeria. Further information:Wikidata:Data access Further information:Wikidata:How to use data on Wikimedia projects Further information:Wikidata:SPARQL query service/Wikidata Query Help/Result Views |
| Wikibase is the software behind Wikidata. It consists of a set of extensions to theMediaWiki software. These extensions allow Wikidata to manage data initems andproperties, and search for this data usingqueries. Further information:Help:Wikibase |
| Wikidata is a Wikimedia project that runs an instance ofMediaWiki with theWikibase extensions. It enablesWikidata editors to enter data and browsepages that display it. Further information:Wikidata:Introduction |
| Wikidata Query Service (orWDQS) is the official service forquerying Wikidata using the SPARQL query language. Further information:Wikidata:SPARQL query service/Wikidata Query Help |
| Wikimedia is the name of a movement which consists of people and organizations. Wikidata is run by the Wikimedia Foundation together with otherwikis such as Wikipedia. TheWikibase software is mainly developed by Wikimedia Germany which is one of the national Wikimedia affiliations. Further information:Help:Wikimedia |
| Wiki is a website that can be edited by the visitors quickly. Wikipedia and Wikidata are wikis. Further information:Help:Wiki |