The hosted domains feature of a hosting account denotes the amount of registered domain names which you can add within the same account. Registering a domain name and hosting it are two different services even though many people consider them to be the exact same thing. While the registration means that you become the owner of a certain domain, the hosting element is what really allows you to have a web site because this is where your files and emails are going to be. As these are two different services, it is possible to register a new domain name with one company and host it with another one by modifying its name servers (DNS) - the domain is going to work in the exact same way just as if it was registered and hosted using the same company. It is also important to know that changing the hosting means pointing the domain name to a different company and not transferring it.