The index is a key-value associative array. The keyterm is the human-readable name, and the value is the location of the leaf on a tree in your Zettelkasten. For instance, here’s an example taken directly from my own Zettelkasten: ‘Truth’: ‘5455/1’. This should look familiar if you’re familiar with data structures like JSON, Python dictionaries, or YAML arrays. You can get pretty advanced with your index and create nested items. However, I won’t cover such now.