A document that defines the fields in a dataset: what each field means, its data type, allowed values, and any business rules.
A data dictionary is essential metadata for any dataset. It allows users who were not involved in creating the data to understand and use it correctly. A good data dictionary includes field names, business names, descriptions, data types, formats, allowed values, and examples.
Data dictionaries are maintained by data stewards and stored alongside datasets or in a data catalog.