A parked domain points a new domain name to the same directory that your primary account points to.
How to setup a parked domain
If you registered your domain with someone besides us, make sure that the name servers are pointing to ns1.yournameserver.com and ns2.yournameserver.com. In your cPanel, select 'Parked Domains' under the 'Domain' menu and enter the domain name you wish to park in the 'Create a New Parked Domain' form.