The template {{defn}} is used in template-structured glossaries to create definitions of terms.
It is a wrapper for <dd>...</dd>, the description list definitionHTML element. The template has a mnemonic redirect at {{dd}}.
Links, inline templates, reference citations, wikimarkup styles, etc., can be applied to the definition. Technically, the |1= part is optional if the content of the definition does not contain the "=" character, but as any editors can add content, including templates with this character in them, it is always safest to explicitly name the parameter. The |1= parameter can also be called |defn= for those who don't care for numeric parameters.
This will work: {{defn|1=The concept that the mass of a body is a measure of its energy content, expressed by the formula E=MC²}}
This will work: {{defn|defn=The concept that the mass of a body is a measure of its energy content, expressed by the formula E=MC²}}
This will fail: {{defn|The concept that the mass of a body is a measure of its energy content, expressed by the formula E=MC²}}
More complex usage is typically:
{{defn|defn=Definition. |no=# |term=term_id}}
where |no=# gives a leading number for a definition in a list of definitions, and |term=term_id provides the name of the term used in the {{Term}} template to which this definition pertains.
Images, hatnotes and other content
Images, hatnotes and other "add-in" content intended to immediately follow the {{term}}must be used at the top of (inside) the first {{defn}} of the {{term}}. They cannot be placed between the {{term}} and {{defn}} or it will break the glossary markup. Images can, of course, be placed elsewhere within the {{defn}}, and bottom-notes like {{more}} can be placed at the ends of but inside{{defn}}s.
{{glossary}}
{{term|1=colour ball |content= colour ball {{anchor|coloured ball|coloured balls|colour|colours|color ball}}}} {{defn|1= [[File:Set of Snookerballs.png|thumb|right|150px|A complete set of snooker balls, with six '''colour balls''']] {{ghat|1=Also '''coloured ball(s)''', '''colour(s)'''; American spelling '''color''' sometimes also used.}}
In [[snooker]], any of the {{cuegloss|object ball}}s that are not {{cuegloss|red ball|reds}}.
}} {{glossary end}}
colour ball
A complete set of snooker balls, with six colour balls
Also coloured ball(s), colour(s); American spelling color sometimes also used.
If a single {{term}} has multiple definitions, they are simply numbered with the |2=parameter explicitly. Think of the parameter as standing for "2nd or later definition". You can also call it |no=, if you prefer (from "No.") Example:
{{glossary}} {{term|1=blubbermonster}} {{defn|1=Lorem ipsum dolor sit amet. |no=1}} {{defn|1=Consectetur adipisicing elit. |no=2}} {{glossary end}}
blubbermonster
1. Lorem ipsum dolor sit amet.
2. Consectetur adipisicing elit.
Because of the uneven length of definitions, it is usually more convenient to put the |2= before the |1= description:
{{defn |2=1 |1=Lorem ipsum dolor sit amet.}}
or
{{defn |no=1 |1=Lorem ipsum dolor sit amet.}}
This is a very robust method, because it permits complex content like block quotations, nested lists, {{main}} cross-reference hatnotes, and other block-level markup inside each definition. The definitions can also be independently linked.
Use of a hatnote with a numbered definition requires manual numbering or it will look weird:
{{term|1=blackjack|content=blackjack{{anchor|Blackjack}} }} {{defn|1={{main|Blackjack}} 1. A card game in which players attempt to approach 21 but not exceed it. }} {{defn|no=2|1=The best possible hand in the game of blackjack, made up of an ace and a card valued at 10 (namely, 10, J, Q, K). }}
Making the definition independently linkable
HTML5 update:
Most of the restrictions on the content of id have been removed, so id values no longer have to begin with an [a-z][A-Z] alphabetic character, avoid most punctuation marks, or suffer other such limitations. Wikipedia's MediaWiki engine is smart enough to auto-escape any problematic characters, on the fly.
To enable a link directly to a specific definition, name the definition with its {{term}} (or it must be the |id=foo value, if any, used in {{term}}). This must be unique on the page for each term, but should be the same for multiple definitions of the same term). This is done with the {{defn}}'s |term= parameter. This will produce a #-link target ID in the form term-defn#, where the # is the number of the definition (see #Multiple definitions for one term, above), defaulting to "1". Example:
{{glossary}} {{term|1=blubbermonster}} {{defn|no=1 |1=Lorem ipsum dolor sit amet. |term=blubbermonster}} {{defn|no=2 |1=Consectetur adipisicing elit. |term=blubbermonster}} {{term|1=snorkelweasel (noun)}} {{defn|1=Ut enim ad minim veniam |term=snorkelweasel (noun)}} {{glossary end}}
blubbermonster
1. Lorem ipsum dolor sit amet.
2. Consectetur adipisicing elit.
snorkelweasel (noun)
Ut enim ad minim veniam
HTML output:
<dl class="glossary">
<dt class="glossary" id="blubbermonster" style="font-size: 110%; margin-top: 0.5em;"><dfn>blubbermonster</dfn></dt>
<dd class="glossary" id="blubbermonster-defn1">1. Lorem ipsum dolor sit amet.</dd>
<dd class="glossary" id="blubbermonster-defn2">2. Consectetur adipisicing elit.</dd>
<dt class="glossary" id="snorkelweasel_.28noun.29" style="font-size: 110%; margin-top: 0.5em;"><dfn>snorkelweasel (noun)</dfn></dt>
<dd class="glossary" id="snorkelweasel_.28noun.29-defn1">Ut enim ad minim veniam</dd>
</dl>
Note that some characters in snorkelweasel (noun)" have been converted on the fly by MediaWikia by the time it sends the ID to the browser as snorkelweasel_.28noun.29-defn1. You can still link to it on this page as #snorkelweasel (noun)-defn1 (view page source and see for yourself – that link has href=#snorkelweasel_.28noun.29-defn1).
The IDs blubbermonster-defn1, blubbermonster-defn2, and snorkelweasel_(noun)-defn1 are all individually linkable, e.g. as [[Glossary of weird terms#blubbermonster-defn1]]. This is especially useful for cross-references within the glossary, e.g. See also [[#blubbermonster-defn2|"blubbermonster", sense 2]].
To add more than one linkable anchor, use the {{anchor}} template at the beginning of the definition's content:
There is no |lang= parameter, as on English Wikipedia all definitions are necessarily in English. For uses of glossary markup for non-glossary purposes in which some content may be in a foreign language, use language templates. E.g. in a list of film title translations formatted using glossary markup:
{{glossary}}
{{term|1=Titles of La Vie en Rose in various languages |content=Titles of ''[[La Vie en Rose]]'' in various languages}}
{{defn|1=French: ''{{lang|fr|La Vie en Rose}}''}}
{{defn|1=English: ''Life in Pink''}}
...
{{glossary end}}
Dømi
This shows both a very simple then a rather complex instance:
==A–M==
{{glossary}}
{{term|1=applesnorkel}} {{defn|1=Definition of term 1.}}
{{term|term=arglefarst |content=''{{lang|xx|arglefarst}}''{{anchor|argle-farst|argle farst}} }} {{defn|no=1 |defn=
Beginning of first definition of term 2 {{gbq|1=Block quotation in first definition of term 2.}}
Conclusion of first definition of term 2. }} {{defn|no=2 |defn=Second definition of term 2.}}
{{glossary end}}
A–M
applesnorkel
Definition of term 1.
arglefarst
1. Beginning of first definition of term 2
Block quotation in first definition of term 2.
Conclusion of first definition of term 2.
2. Second definition of term 2.
Applying CSS styles to the definition
The |style= parameter will pass CSS styling on to the <dd> element, e.g. |style=font-family:serif; or whatever. I.e., this styles the definition itself, not the term it applies to, other defintiions, or the glossary as a whole. This feature is rarely if ever needed in articles, but can be useful elsewhere for things like matching custom user page style.
Other parameters
The |id= parameter can be used to assign a one-word, case-sensitive ID name to definition. It must be unique on the page. This can be used as a #link target, and could have other metadata uses. See the #Making the definition independently linkable section for how to normally make a definition linkable. Probably the only reason to use this feature is if there are two terms with the same name on the page, which would result in conflicting IDs.
The |class= parameter will pass one or more space-separated CSS classes on to <dd> element, in addition to the automatically included class glossary. There is rarely any reason to do this.
The template {{glossary}} (a.k.a. {{glossary start}} or {{glossary begin}}) is used with {{glossary end}} to explicitly bracket a glossary or glossary-like description list (also called a definition list or association list), especially in a template-structured glossary, although such lists can be used more generally. This is required (as a technical matter) for template-structured glossaries, and is good practice anywhere description/definition lists are used for glossaries. The template pair invoke the <dl>...</dl>description listHTML element. Unfortunately, the "{{dl}}" mnemonic is not available as a redirect as of this writing.
The pair of templates incidentally prevent Wikipedia's MediaWiki software engine from auto-creating redundant definition list code (<dl>...</dl>) around terms and definitions if they have blank lines between them, as they often do, especially in non-structured glossaries.
|id= can be used to assign a one-word ID name to the glossary. This can be used as a #id link target, and could have other metadata uses.
|style= will pass CSS styling on to the <dl> element. I.e., this styles the definition list itself, as a container, not the individual terms and definitions with it. There is rarely any reason to do this.
|class= will pass one or more space-separate CSS classes on to <dl> element, in addition to the automatically included class glossary. There is rarely any reason to do this.
Examples
This shows both a very simple then a rather complex instance in a structured glossary (including an entry with a block quotation, using the glossary block quotation template, {{gbq}}):
==A–M==
{{glossary}}
{{term|1=applesnorkel}} {{defn|1=Definition of term 1.}}
{{term|term=arglefarst |content=''{{lang|xx|arglefarst}}''{{anchor|argle-farst|argle farst}} }} {{defn|no=1 |defn=
Beginning of first definition of term 2 {{gbq|1=Block quotation in first definition of term 2.}}
Conclusion of first definition of term 2. }} {{defn|no=2 |defn=Second definition of term 2.}}
{{glossary end}}
A–M
applesnorkel
Definition of term 1.
arglefarst
1. Beginning of first definition of term 2
Block quotation in first definition of term 2.
Conclusion of first definition of term 2.
2. Second definition of term 2.
Scope
This family of templates, like the underlying definition list code, is primarily intended for definitional uses, but can have other applications. The HTML 4.01 Specification itself says:
Definition lists...generally consist of a series of term/definition pairs (although definition lists may have other applications). Thus, when advertising a product, one might use a definition list:
Lower cost
The new version of this product costs significantly less than the previous one!
Easier to use
We've changed the product so that it's much easier to use!
Safe for kids
You can leave your kids alone in a room with this product and they won't get hurt (not a guarantee).
Thus, editors should feel free to use definition list markup as an alternative to bulleted or numbered lists when the material is well-suited to definition list presentation.
The template {{term}} is used in template-structured glossaries to create terms to be defined, that are properly structured, have semantic value, and can be linked to as if independent sections. It is a wrapper for <dt>...</dt>, the description list termHTML element. The template has a mnemonic redirect at {{dt}}.
Inline templates, reference citations, wikimarkup styles, etc., can be applied to the term in the second parameter (|content= or |2=) as long as it remains without markup in the first parameter (|term= or |1=). Technically, the explicit parameter names are optional if the term or content does not contain the "=" character, but as any editors can add material, including templates or URLs with this character in them, it is always safest to explicitly name or number the parameters.
This will work: {{term|term=E=MC²}}
This will work: {{term|1=E=MC²}}
This will fail: {{term|E=MC²}}
More complex usage is typically:
{{term|term=term with no markup |content=term with markup}}
or
{{term|1=term with no markup |2=term with markup}}
or
{{term|1=term with no markup |content=term with markup}}
Wiki-styling and linking the term
If the second or |content= parameter is styled with wikimarkup, linked, or otherwise altered inside the template, the term must also be retained in unstyled form as the first or |term= parameter. Failing to do so will cause the template to malfunction, since it must have a "clean" term name to use as the id of the element, for linking purposes, among other reasons. The order intentionally mirrors that of wikilinking ([[title|styled]]).
Correct: {{term|1=esprit de corps|''esprit de corps''}}
Wrong: {{term|1=''esprit de corps''}}
Style cannot be applied around the template, either, as it is a container for content (the term), not content itself (and doing so will produce invalid markup that will have unpredictable results depending upon browser):
Wrong: ''{{term|1=esprit de corps}}''
For the same reasons that links to other pages are discouraged in headings, links are discouraged in glossary terms:
Deprecated: {{term|1=esprit de corps|''[[esprit de corps]]''}}
Preferred: {{term|1=esprit de corps|''esprit de corps''}}, and use of a {{ghat}} hatnote in the {{defn}} definition to link to the main article Esprit de corps.
Again, as with the first parameter (the term) itself, if the "=" character (equals sign) is used in this second parameter, the syntax requires that the parameter be explicitly specified (and because many URLs, e.g. in reference citations, can contain this character, it is always safest to number or name the parameters):
numbered:
{{term|1=E=MC²|2=E=MC<sup>2</sup>}}
or named:
{{term|term=E=MC²|content=E=MC<sup>2</sup>}}
The template {{anchor}} can also be used in the |content= a.k.a. |2= parameter, e.g. to provide the plural of the term (the most common usage), an alternative spelling, the old name of an entry that was linked to but has since changed, or a shortcut link anchor name:
As with styled terms, the second parameter must be used to provide the "bare" term. It is not necessary to add the term itself to the {{anchor}} template when using {{term}}. By contrast, when using semicolon-delimited terms in unstructured glossaries, the term does need to be added as an anchor explicitly if link anchorage is desired (which is almost always the case):
(Strictly speaking, this fact has nothing to do with this template, but may be of use to editors who are converting from one glossary style to the other.)
Multiple terms sharing a definition
Two or more {{terms}} can be used for synonyms with a shared definition, though keep in mind that people looking for one and not finding it where they expect it to be alphabetized are liable to assume it is missing if you do not create a cross-reference entry. The parameter |multi=y is used on second and subsequent terms to visually group the terms close together so it is clear that they share a definition:
Example:
{{term|1=aspirin}}
{{defn|1=A mild analgesic of the non-steroidal anti-inflammatory drug (NSAID) family...}}
{{term|1=heroin}}{{term|1=diacetylmorphine |multi=y}}{{term|1=diamorpine |multi=y}}
{{defn|1=A synthetic narcotic drug of the opiate family...}}
{{term|1=ranitidine}}
{{defn|1=An antacid of the proton pump inhibitor family...}}
Result:
vs. no |multi=y
aspirin
A mild analgesic of the non-steroidal anti-inflammatory drug (NSAID) family...
heroin
diacetylmorphine
diamorpine
A synthetic narcotic drug of the opiate family...
ranitidine
An antacid of the proton pump inhibitor family...
aspirin
A mild analgesic of the non-steroidal anti-inflammatory drug (NSAID) family...
heroin
diacetylmorphine
diamorpine
A synthetic narcotic drug of the opiate family...
ranitidine
An antacid of the proton pump inhibitor family...
Languages
To indicate the language of a non-English term, use the {{lang}} template and the ISO 639 language codes as documented at that template:
{{term|1=esprit de corps |content=''{{lang|fr|esprit de corps}}''}}
This shows no visual change for most languages:
esprit de corps
For all non-English languages this provides many metadata features, but it is essential for those that do not use the Latin alphabet, so that the content displays properly in various browsers.
If it is useful to indicate the name of the language, there are individual templates for most languages, with names based on the ISO codes, and which automatically italicize the foreign content:
{{term|1=esprit de corp |content={{lang-fr|esprit de corps}}s}}
which renders as:
When two or more language variants of a term share the same definition:
As detailed above, two or more terms, as variations or alternatives, can share definitions. The most common use case for this is presenting the term in two variants of English. Example:
{{term|1=tyre|content={{lang-en-GB|tyre}}}}
{{term|1=tire|content={{lang-en-US|tire}}}}
{{defn|1=A resilient wheel covering usually made of vulcanized rubber.}}
Result:
A resilient wheel covering usually made of vulcanized rubber.
The template has no |lang= parameter (and shouldn't – there are too many pitfalls).
Applying CSS styles to the term
The |style= parameter will pass CSS styling on to the <dt> element, e.g. |style=font-family:serif;. I.e., this styles the term itself, not the definitions of it, other term entries, or the glossary as a whole. This feature is uncommonly but sometimes importantly needed in articles (usually for formatting the appearance of an specific entry for some reason, e.g. certain mathematical constants and the like that are always given in a serif font). It can also be useful outside of articles, for things like matching custom projectpage or userpage style.
Other parameters
HTML5 update:
Most of the restrictions on the content of id have been removed, so id values no longer have to begin with an [a-z][A-Z] alphabetic character, avoid most punctuation marks, or suffer other such limitations. Wikipedia's MediaWiki engine is smart enough to auto-escape any problematic characters, on the fly.
The |id= parameter can be used to assign a one-word, case-sensitive ID name to term. It must be unique on the page. This can be used as another #link target, and could have other metadata uses. By default, the |term= a.k.a. |1= parameter is already set as the ID, and this should rarely be overridden, unless there are two identical terms on the same page creating conflicting IDs. Usually the {{anchor}} template is used to add more link targets to an entry (see #Wiki-styling and linking the term for details).
The |class= parameter will pass one or more space-separated CSS classes on to the <dt> element, in addition to the automatically included class glossary. There is rarely any reason to do this.
Examples
This shows both a very simple then a rather complex instance:
==A–M==
{{glossary}}
{{term|1=applesnorkel}} {{defn|1=Definition of term 1.}}
{{term|term=arglefarst |content=''{{lang|xx|arglefarst}}''{{anchor|argle-farst|argle farst}} }} {{defn|no=1 |defn=
1. Beginning of first definition of term 2 {{gbq|1=Block quotation in first definition of term 2.}}
Conclusion of first definition of term 2. }} {{defn|no=2 |defn=Second definition of term 2.}}
{{glossary end}}
A–M
applesnorkel
Definition of term 1.
arglefarst
1.
Beginning of first definition of term 2
Block quotation in first definition of term 2.
Conclusion of first definition of term 2.
2. Second definition of term 2.
Images, hatnotes and other content
Images, hatnotes and other "add-in" content intended to immediately follow the {{term}}must be used at the top of (inside) the first {{defn}} of the {{term}}. They cannot be placed between the {{term}} and {{defn}} or it will break the glossary markup. Images can, of course, be placed elsewhere within the {{defn}}, and bottom-notes like {{more}} can be placed at the end of, but inside, a {{defn}}. When used with a multi-definition term, the definition in which the {{ghat}} appears must be manually numbered (usually 1 ..., as shown in the example below).
{{glossary}}
{{term|1= colour ball |content=colour ball {{anchor|coloured ball|coloured balls|colour|colours|color ball}} }} {{defn| 1= [[File:Set of Snookerballs.png|thumb|right|150px|A complete set of snooker balls, with six '''colour balls''']] {{ghat|Also '''coloured ball(s)''', '''colour(s)'''; American spelling '''color''' sometimes also used.}}
1. In [[snooker]], any of the {{cuegloss|object ball|object balls}} that are not {{cuegloss|red ball|reds}}.
}}
{{defn|no=2 |1=
In [[Blackball (pool)|blackball]], a generic, collective term for the red and yellow {{cuegloss|group|groups}} of object balls.
}} {{glossary end}}
colour ball
Also coloured ball(s), colour(s); American spelling color sometimes also used.
A complete set of snooker balls, with six colour balls
1. In snooker, any of the object balls that are not reds.
2. In blackball, a generic, collective term for the red and yellow groups of object balls.
Technical details
What this template does on the technical level is wrap the term in the <dfn>...</dfn>HTML element to semantically mark the term as the defining instance on the page of the defined term, and puts this marked-up content inside a <dt>...</dt> description list (a.k.a. definition list, association list) term element, with CSS class="glossary". That class isn't doing anything yet, but it could later, like the light font size increase.
