Hello Amira,

synonyms is an alternative name for objects such as tables, views, sequences, stored procedures, and other database objects.

You generally use synonyms when you are granting access to an object from another schema and you don’t want the users to have to worry about knowing which schema owns the object.

and here is the syntax to create synonym

CREATE [OR REPLACE] [PUBLIC] SYNONYM [schema .] synonym_name
FOR [schema .] object_name [@ dblink];

Example:

CREATE PUBLIC SYNONYM emps
FOR app.employees;

Hope this help.