The hosted domains feature of a website hosting account indicates the amount of registered domain names which you can include in the exact same account. Registering a domain address and hosting it are two completely different services although many people consider them to be the exact same thing. While the registration ensures that you become the owner of a certain domain name, the hosting part is what actually permits you to have a website as this is where your data and e-mails are going to be. Because these are two independent services, you can register a new domain address with one company and host it with another one by modifying its name servers (DNS) - the domain address will work in the exact same way just as if it was registered and hosted with the exact same company. It's also extremely important to know that changing the hosting means pointing the domain to another company and not transferring it.