The hosted domains feature of a website hosting account indicates the number of registered domains that you can add in the very same account. Registering a domain and hosting it are two different services although a lot of people consider them to be the same thing. While the registration signifies that you become the owner of a certain domain, the hosting part is what in fact permits you to have a website as this is where your files and emails will be. As these are two independent services, it is possible to register a new domain name with one company and host it with another by modifying its name servers (DNS) - the domain name shall work in the exact same way just as if it was registered and hosted with the exact same company. It is also extremely important to know that changing the hosting means pointing the domain address to a different company and not transferring it.