Board Thread:Support Requests - Designing Your Wiki/@comment-26945995-20170609144033/@comment-168424-20170609184434

The term you're thinking of is called "transcluding".

Put  tags around the synopsis. You can only use one set of these tags, so a safer way is to put the synopsis in subpage like w:c:dgrayman:D.Gray-man/synopsis and then transclude it to both places with.