Transclusion is the technique to render parts of one document within another document.

The PDAC1 provides macros to define content within a document to be transcluded (for instance the Section Macro and the Content Marker Macro) and macros to transclude this content into a document (for instance Transclusion Macro and Transclude Documents Macro).

Note that the projectdoc Toolbox makes it easy to list documents that transclude from a document (see Module) and there are tools for authors (see Transclusion Box) to make jumping to transcluded content very easy.