ABAP Dictionary centrally describes and manages all the data definitions used in the system and the database. It is completely integrated in the ABAP Development Workbench. ABAP Dictionary supports the definition of user-defined types i.e. data elements, structures and table types. These types are used in the ABAP processors and ABAP programs. It also defines the structure of database objects i.e. tables, views and indexes.
In this document, you will get an overview of ABAP dictionary and predefined data elements.