Warhammer 40k - Lexicanum:Internal link
An Internal link is a link in the Lexicanum to another page or resource in the Lexicanum - as opposed to an External link which is a link leading to a page or resource outside the Lexicanum.
Internal links are the underlying cross-link system that connects Lexicanum pages with each other, thus creating the internal navigation system needed for an efficient and user-friendly Lexicanum experience. Without Internal links a reader is not able to jump from one page to another without having to enter a new search term into the Search mask. Or in other words: A Lexicanum page without Internal links is a dead-end page for a reader instead of a versatile navigation point from which he/she can comfortably navigate to other pages that are related or of further interest. Therefore Internal links are essential and possibly the most important feature of any wiki.
Generally speaking and given the importance of Internal links (see above) it is obvious that this type of link is used ubiquitously throughout all pages of the Lexicanum. As a rule of thumb every page in the Lexicanum that exists or should exist has to be linked to via an Internal link. There is (almost) no such thing as "over-linking", i.e. "overdoing" it with Internal links, for details see below.
The most important use of Internal links is - as said before - to cross-link individual articles. As a general rule every page that exists or should exist in the Lexicanum has to be linked to whenever it is referenced on a Lexicanum page. The only restriction to "whenever" basically being that linking once to every relevant term in one paragraph is sufficient, i.e. if the term Space Marine is used 25 times within the same passage of a page you should not create 25 identical Internal links to Space Marine. But with every new paragraph this theoretical "counter" is reset to zero, i.e. you have to re-link to the relevant pages, no matter if they were already linked-to in a previous paragraph on the same page.
Obviously Internal links are also the format to use in the See also section of an article.
Another very important point to note is that Internal links should not only be created to already existing pages in the Lexicanum - but explicitly also to not-yet existing articles (these links are often colloquially called "red links" after the colour they are displayed in on a page as opposed to "brown" links to existing pages). This has two reasons: First of all if an Editor fails to create Internal "red" links all these links will have to be created retroactively once the intended target page has been created - an unnecessary additional complication. The second reason is that the Wikimedia tool "Wanted pages" only processes Internal links. If there are no internal links, the system cannot recognize which pages would be urgently required to be created.
The second most important use of Internal links is in Citations - most sources must be formatted as Internal links. The reason for this is simple: Every legitimate source has or should have its own Lexicanum article. There are a few exceptions when sources have to be formatted as External links which are explained on the corresponding Help page.
Notes: All Naming and other writing conventions must be observed! It should also be noted that Internal links should directly point to the correct target page, i.e. for example not to a Warhammer 40k - Lexicanum:Redirect page.
To include an Internal link on a page you have to include the code [[Target pagename]] on the chosen page.
If you want to link to the page entitled "Planetary Defense Forces":
[[Planetary Defence Forces]]
You can also internally link to a specific section of a page instead of to the page as such. For example if you want to link to a section of another page (which must exist of course!) you have to include the code [[Target pagename#Section name]] on the chosen page.
If you want to link to the section entitled "System_Defence_Forces" which is a section on the page Planetary Defense Forces:
[[Planetary Defence Forces#System Defence Forces]]
Diverging display text
The default function of an Internal link is to display the title of the target page. For stylistic and other reasons is however often necessary or desirable that a different, more specific or otherwise more appropriate display text is shown in the article (while the Internal link of course still points to the correct target page). To achieve this effect you have to include the code [[Target pagename|display text]] on the chosen page.
If you want to link to the page entitled "Planetary Defense Forces" but wish that the displayed text in the article is "Imperial forces already present":
[[Planetary Defence Forces|Imperial forces already present]]
This practice obviously also works with sections of articles.
If you want to link to the section entitled "System_Defence_Forces" which is a section on the page Planetary Defense Forces but display the text "Imperial forces already present in the star system":
[[Planetary Defence Forces#System Defence Forces|Imperial forces already present in the star system]]
Singular, plural, adjectives etc.
Using the singular, plural, adjective etc. of a Lexicanum term and still internally link to the correct target page can be realized like described in the previous section. In some simple cases where just one (or more) letter(s) are attached at the end of the linked-to target page name there is also another possibility.
If you want to link to the planet Cadia but need to use the adjective "Cadian" in the article:
If you want to link to Ork but need to use the plural "Orks" in the article:
This principle can be extended to any similar cases.
The Lexicanum is available in three languages. Interlexicanum internal links (in some cases also known as "interlanguage links") are used to connect the different Lexicanum projects, i.e. not only the different language versions, but also the Warhammer 40,000 and Warhammer settings via Internal links.
For a detailed description and instructions how to use these Interlexicanum internal links see here.
Special case: Wikipedia
While technically speaking Wikipedia is an external website (i.e. it is outside of the Lexicanum) the Mediawiki software used in the Lexicanum allows to treat Wikipedia external links as if they were Internal links in the Namespace "Wikipedia". The latter means that in front of the intended target page name the prefix "Wikipedia:" must be added. So a complete Wikipedia link would look like this: [[Wikipedia:Target page name]] (or of course [[Wikipedia:Target page name|display text]]).
If you want to link to the Wikipedia article on Warhammer 40,000:
[[Wikipedia:Warhammer 40,000|Warhammer 40,000 (Wikipedia)]]
All formatting rules and instructions for "normal" Internal links should be applied to these Wikipedia pseudo-Internal links. Please do note that it should be either explicitly clear or logical from the context when a link to Wikipedia is included on a page.