You've come across a word that is crucial to understanding the article you are working on, and you want to create a link to its definition. But you find the encyclopedia article for that word would be overkill. So you want to link to its Wiktionary definition. How? It's easy. Here's an example using the word "understanding":

both [[wiktionary:understanding|]] and [[wikt:understanding|]] will look like this:

understanding

and link to the definition of the word "understanding".

Notice that the "pipe trick" (|) was used in the links above.