Help:Transclusion

 is the inclusion of the content of a document into another document by reference. For example, an article about a country might include a chart or a paragraph describing that country's vital records from another article about important genealogical records. Rather than copying the included data and storing it in two places, a transclusion embodies modular design by allowing it to be stored only once (and perhaps corrected and updated if the link type supported that) and viewed in different contexts. The reference also serves to link both articles.

In the Wikipedian context, it is the use of the template messages to include the same content in multiple documents without having to edit those documents separately. Template transclusion is the common way to use template messages, and is implemented by using a template tag, with this form:



One may want to use a template, but for one reason or another may not want to use transclusion. The automatic one-time copying of a template's code/text to the location of a template tag is called Template substitution or subclusion (substitution + transclusion). To subclude a template's code/text, the template tag is modified from the standard transclusion tag to a substitution tag, simply by adding, creating a tag with the form:.