Transclusion is generally the inclusion of the content of a document into another document by reference. In the context of Bahaipedia, it means using the template functionality of MediaWiki to include the same content in multiple documents without having to edit those documents separately.
As an example, consider the page Template:DateToBahai. When the name of that page is placed between double curly braces (like so: {{DateToBahai}}) in the wikitext of a page, it will display the content of that page, like this: 3 Kamál, 182 BE. MediaWiki interprets the double curly braces ( {{ }} ) as syntax for transcluding a page. By using this syntax, you can include the contents of a page anywhere else on a wiki.
