A tiddler is an entry in a TiddlyWiki. It is equivalent to a wiki page and uses a simplified markup language similar to that used by Wikipedia. In fact the original source text for this entry was entered in a TiddlyWiki and yielded pretty much the same display. Compared to a Wikipedia page though, there are some interesting differences:
When a user wishes to update their TiddlyWiki copy from the originating TiddlyWiki, either to get a bug-fix or new functionality, the standard update procedure never changes tiddlers. This discipline ensures that the user never loses their own TiddlyWiki's content.