The "Codes" screen registers and changes codes. A code is a list of values with a common denominator. Application development widely uses codes to construct domains. A domain can, for example, store a list of values for a field. The "Revenues" screen, for example, shows a code list for the number of periods. Registering codes is a typical activity for application developers. See the warning under Application Development. The entry fields are: - "Code": The code that refers to the code list. - "Description": The description of the code list.