Can you tell me what is exactly the .world domain in Oracle.

I create a new database in a new server. It seems that it inherits another domain by default so from client machine since I have names.default_domain = WORLD in sqlnet.ora everytime i want to connect to this database I have to use something like
connect scott/tiger@db_prod.xyz.com

How can I get rid of specifying xyz.com everytimeand keeping the names.default_domain as WORLD.

It is very important for our applications. PLease advice.