The hosted domains feature of a hosting account denotes the number of registered domains which you can add in the exact same account. Registering a domain address and hosting it are 2 totally different services even though many people consider them to be the same thing. While the registration means you become the owner of a specific domain address, the hosting aspect is what really enables you to have a site because this is where your data and e-mails will be. Because these are two separate services, you can register a new domain with one company and host it with another one by changing 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 is also important to know that changing the hosting means directing the domain name to a different company and not transferring it.