The main components of the Data Dictionary are a tree structure of resources, fields and lookups (aka enumerations). Resources are major categories such as Property, Member (i.e., real estate agents), Office (i.e., real estate brokers) and Media (i.e., photographs, videos, virtual tours). Fields are specific data points grouped together in resources. For example, ListPrice and StandardStatus are fields within the Property Resource. Lookups are specific types of fields with options for values, such as the lookup field Fencing with lookup options for Vinyl, Wood, Wrought Iron and 26 other lookups.
More Info on Data Dictionary
