Oracle can mean Oracle Corporation or Oracle Database among other things.
Oracle Database is defined in the Concepts Guide http://docs.oracle.com/cd/E11882_01/server.112/e25789/intro.htm#i57253:
Oracle Database is an RDBMS. An RDBMS that implements object-oriented features such as user-defined types, inheritance, and polymorphism is called an object-relational database management system (ORDBMS). Oracle Database has extended the relational model to an object-relational model, making it possible to store complex business models in a relational database.
Why did you post your question in Data Guard forum ? Data Guard is an Oracle Database feature.
You cannot move your questions to another forum: only forum moderators can do that.
If you have general questions about Oracle Database it is better to use the General Questions forum General Questions