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.
Wikipedia shows the idea in action. 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.
Why you care
Wikilinks are how a knowledge base stops being a pile of disconnected documents. A meeting note can link to the client, the project, and the decision the meeting produced, and an agent can read one note and follow the links to gather context instead of you pasting every relevant file into the chat. A good link earns the click, though. Don’t wikilink words just because they sound important: a wikilink should point to a real note, and a link to a note that doesn’t exist is a promise the system can’t keep. That’s how a second brain gets noisy.