BC - ABAP Dictionary 

The ABAP Dictionary centrally describes and manages all the data definitions used in the system. The ABAP Dictionary is completely integrated in the ABAP Development Workbench. All the other components of the Workbench can actively access the definitions stored in the ABAP Dictionary.

The most important object types in the ABAP Dictionary are tables, views, types (data elements, structures, table types), domains, search helps and lock objects.