Metadata is information that provides context and description of data. There are many synonyms for metadata, including "data about data", "information about information", "descriptor data", "schema data", "attribute data", "catalogue data" and "structural data". Other synonyms for metadata include "header data", "administrative data", "secondary data", "contextual data", "relational data", and "reference data". All these synonyms help to describe the purpose and function metadata plays in data management. Regardless of the name given to metadata, the crucial understanding is that it provides critical information to help understand and manage the underlying data.