A wikilink is written with double brackets, like [[vault|vault]], and it points to another note by name rather than by URL. Inside a vault, that makes linking fast, readable, and durable: the link says this concept has its own note, and this note is connected to it.
The analogy is Wikipedia. You read one article, see a linked word, click it, and move to the related article. You don’t need the whole internet explained on one page. The links let you move through connected knowledge one useful step at a time.
How it shows up
When you’re building a knowledge base, wikilinks are how the system stops being a pile of disconnected documents. A meeting note can link to the client, the project, and the decision the meeting produced. For AI work this is especially helpful: the agent can read one note and follow the links to gather context instead of relying on you to paste every relevant file into the chat. It doesn’t mean the agent magically understands everything. It means you’ve given it a map of the relationships.
Why you care
A good link earns the click, the way a good Wikipedia link points to the article that actually helps. Don’t wikilink words just because they sound important. A wikilink should point to a real note or glossary term; if the target doesn’t exist, the link becomes a promise the system can’t keep, and that’s how a second brain gets noisy. In a glossary, wikilinks also help the reader move through concepts in the order their confusion appears.