Data that describes other data — providing context about what a dataset contains, where it came from, and how to use it.
Metadata is often called data about data. For a dataset, metadata might include: the title, description, creator, creation date, update frequency, geographic coverage, licence, and column definitions.
Good metadata makes data findable, understandable, and trustworthy. Without metadata, even valuable data can be unusable because nobody knows what it contains or how to interpret it.