The hosted domains feature of a web hosting account indicates the number of registered domains that you can include within the very same account. Registering a domain and hosting it are 2 different services although a lot of people consider them to be the exact same thing. While the registration means you become the owner of a given domain address, the hosting part is what really enables you to have a web site since this is where your files and e-mails are going to be. Since these are 2 separate services, you can register a new domain name with one company and host it with another one by changing its name servers (DNS) - the domain is going to work in the exact same way just as if it was registered and hosted with the same company. It's also important to know that changing the hosting means pointing the domain name to another company and not transferring it.