A data dictionary usually contains a working definition of each element, the values that are allowed, location information, and additional metadata deemed important for an organization to maintain about its data assets. Data Value -an instance of a data element. For example, John J. Jones is a name of a specific person. For example, M and F may be the domain for the data element Gender. Repository -Information about the data in an organization's electronic systems.
Data dictionaries are forerunners to repository.