Data Area 

All data volumes in a database instance are known collectively as the data area. The data area contains, amongst other things, the application data, the database catalog and the undo log entries of the database instance.

See also:

Concepts of the Database System, Volumes (Permanent Memory)

Database Manager GUI, Displaying Data Area Information

Database Manager CLI, show

Database Administration in CCMS: MaxDB, Monitoring the Data Area

Database Administration in CCMS: SAP liveCache Technology, Monitoring the Data Area