Transclusion is pulling content dynamically from one page into another page. Rather than cutting and pasting text from one page to another, you create a pointer to the page you are borrowing from. That pointer is resolved at run time, pulling content from the other page when your page is loaded. Transclusion was a fundamental part of Ted Nelson’s original concept of hypertext. It has never caught on, except in specific confined circumstances. Despite continued interest, it isn’t going to catch on.