The ABCs of Data Dictionaries.

A data dictionary is a document containing descriptions of the data elements in a data system. Examples are the data element name, length of allowed characters for storing the data element, definition, and other technical information (e.g., how and where the data were collected, data format, how the data relate to other data). A data dictionary should be easily accessible to users and managers of a data system. Just as a typical dictionary helps convey the meaning of words, a data dictionary translates data elements into real-world terms. A data dictionary also helps users prepare data elements to be compared or merged with data from other systems.