With a Zettelkasten, it’s an absolute breeze to look for specific definitions, concepts, thoughts or ideas. All that is needed is to search for the relevant note by title.
In a Zettelkasten, a note deals with one and only one topic, and its title allows you to very easily find it. When deepening knowledge on a specific topic, you go into that topic’s note and expand it. This reflects how we (or at least I do) store knowledge in our brain.
This contrasts with other note-taking methods. At university, I see many people take sequential notes. These notes not only have many other drawbacks (e.g. they don’t force you to do your own thinking), but they are also terrible for looking for a specific concept or idea. You have to look through many many chronologically (or otherwise) ordered notes to find something specific, and even then, tidbits of it may be distributed along several notes.