There is a parked domain / Park a domain option in some webhost control panel. This option is to add your domain names that you want to be parked.
What does this term mean exactly? well, they allow you to make a parked page, and make it like what you want it to appear, and then you can point all the parked domains that you add to park a domain option, will show that parked page when accessed through browser.
This option allows you to have a temporary page for your domain until you design or upload a final page for that domain name. Mostly people like giving a coming soon message and / or ads from google adsense or any other ads service provider on their parked pages.