For example, assume you have the several domain names that are currenty not in use, and you would like them to point to your main domain. You can park the additional domains.
By parking the additional domains, someone who goes to www.another-domain-03.com will end up at my-main-domain-name.com.
The number of domains that can be parked is dependent on your subscription level.
You can set up parked domains through your web based control panel.