Metadata
Data about the data: source, license, last-updated date, and field definitions, not the records themselves.
Metadata describes a dataset without being part of its rows: where the data came from, when it was last verified, what license governs it, who maintains it, and how each field is defined. Metadata is what lets a buyer or an AI system trust a dataset enough to actually use it.
Example
A dataset's `updated_at`, `license`, and `fields` definitions are metadata. The 5,000 business records inside it are the data itself.